I have never written a review of a Linux distribution, but I've read more than I can count, and many of them have been maddeningly incomplete and not worth the time it took to read them. Here's a list of items you need to talk about in order to write a thorough review, covering every aspect of the distribution from the initial download to the final recommendation and everything in between.
Not every item below applies to every distribution; you need to choose which items to include and which to ignore. For example, if the distribution is for an embedded device, there's probably not much point in discussing window manager themes. However, the more you include, the better your review will be. You can cover some of this information in a simple table, but many of the points deserve more explanation.
In addition to talking about each item, you should tell your readers how important or useful you think each item is. For example, if the distribution automatically boots all the way to a logged-in guest account, do you like this or not?
Purpose of distribution
Describe the purpose of the distribution as given by the creators. For example, the distribution may be intended for servers or it might instead be for multimedia creators. If the creators do not list a purpose, you can give your view, but this should be done in a later section where you describe your impressions and recommendations.
Describe the "parent" distribution this distribution is based on. For example, is this distribution Slackware or Debian based? If it is not based on a parent distribution, discuss the implications of this. Spend more time on this point if the parent distribution is particularly relevant -- for example, is the distribution intended to be minimalist but was built on the biggest kernel around?
Give the version number of the distribution you are reviewing. What is the release date? Is this the latest version? If not, explain why you are you reviewing an older version. For example, the latest version might be beta and you only want to review the latest stable release. Which kernel is the distribution based on? Does the distribution contain multiple kernel versions? Don't just list the kernel as "2.6" but rather give the minor release number also (e.g. 2.6.25). Note whether the kernel is recent or older and discuss the distribution release dates versus the kernel release dates if that is relevant. For example, if the distribution is only days or weeks old but the kernel version is much older, note this. If the distribution uses a special kernel, include the bug fix number (e.g. 188.8.131.52).
Mention the distribution creators -- is it one person working out of his home or is the distribution from a large scientific or government body?
Describe the methods provided to get the distribution. List the size of the distribution. Are there mirrors in major regions or is the distribution only available on its Web site? How fast was the download? How did you find out about this distribution? Are there other formats available? For example, can one purchase a DVD or CD? Is this a commercial or a free release?
List the CPU architectures the version supports. Tell the readers whether one download supports multiple architectures, and about any special architectures that are supported.
Live vs. install
Say whether the distribution requires an install before you can use it fully. Most distributions have a live CD version. List the various "flavours" the distribution comes in. For example, are there separate minimal and full versions? Are there versions for different kinds or users or for different computer architectures?
Live CD issues
Describe the distribution's approach to saving personal files while in live CD mode. Are there any ways of saving the configuration? Does the distribution have a control panel entry for this? How easy is it to restart the live CD version and apply your saved configuration?
Discuss the tools and process of installing the distribution onto the hard drive. How much manual intervention is required? How much technical expertise is needed? How well is the process documented? Does the system automatically partition the drives? Does it automatically backup existing files? Which filesystems are supported? Is there a default filesystem?
Since you will likely write your review in English (since you are reading this guide in English) then if the default language is not English emphasize the point. List the languages supported by the distribution. What is the default language? How well supported are the other listed languages? For example, if English is not the default language, do applications and documentation switch to English when you switch the language to English?
Describe which boot parameters are required and which boot options are available. Does the distribution stop and ask for user input or does it boot automatically? Even if it does boot all the way to a graphical desktop, does it still require configuration settings in the desktop? For example, some distributions will run all the way to a logged-in user running X but then show a dialog box requiring the person to set up the network card.
Describe the ease of modifying the boot parameters, especially if you had to change any of the defaults in order to get the distribution working on your machine. Were there function keys that changed the default resolution or runlevel? Describe the level of documentation provided on the boot screens themselves. For example, did you have to already know that you should type "noapci" or did the boot screens explain all that and all other "cheat codes" (at least the ones required to get your machine working)?
Tell the user if the system boots with a splash screen. This is particularly important if the distribution is intended for novice users. Does the distribution show any boot output or is it fully hidden?
Describe the startup scripts that come with the distribution. Besides startx, are there separate start scripts for each window manager? How easy is it to find them (i.e. are they documented clearly)? Are there start scripts for services like CUPS and firewalls?
Graphical vs. text
Explain what happens when the system has finished booting. Does it automatically start an X session? Which version of X does it use? If it doesn't start X automatically, what does it do? What sorts of instructions are given on screen, regardless of the boot mode? Is there enough information given to tell the user how to log in? For example, for any distribution intended for novice users, are the username and password shown on the login screen?
Discuss the video mode the system boots to by default if it boots to X. Does it automatically find and use the highest resolution or possibly the highest refresh rate? Is the boot video mode selectable at some point?
Describe the automatic hardware detection of the distribution. This includes but is not limited to video cards, audio cards, keyboards, mice (including the scroll wheel), USB ports, hard drives, CD and DVD devices, modems, network cards, printers, and scanners. Are the correct video drivers loaded? If you plug in or remove USB devices, does the system correctly configure the devices? Does your sound card work? Which sound architecture does it use?
Tell whether the hard drives are mounted in read-only or in read-write mode. Can the distribution read and write non-Linux drives? How easy is it to switch between read-only and read-write? Were all the hard drives automatically mounted?
Discuss how the distribution configures the network devices. Are they all discovered? Does the system let you use DHCP? How much manual configuration is required? What tools are provided for managing the network?
Describe whether wireless network cards are properly configured. On startup, does the system tell you whether it tried, and what the result is? Are there any special tools to help you manage wireless connections?
Describe the printer setup process. Print some documents. Is CUPS automatically started? How easy is it to add a printer? Which printers are supported?
If you run the distribution on a laptop, discuss how well the hardware is supported. Does the distribution correctly deal with putting the laptop into sleep and hibernate modes? Is the infrared port configured? Does it support Bluetooth?
Mention the login manager that starts by default. You can also list other supplied login managers, if any.
List all the window managers supplied with the distribution and their version numbers. Does the login manager (if any) list the window managers and allow the user to select one different from the default? Are there window managers included that aren't shown by the login manager? Are there any unusual window managers?
Discuss the themes provided. How easy is it to change themes and get new ones?
Look and feel
Discuss the overall look of the distribution. Is there a consistent feel starting from the boot loader and going all the way through the login manager, default themes, and any customized control panels?
Discuss the fonts that are installed with the distribution. Note anything exceptional, such as a large number of unusual fonts.
Describe the desktop. Which applets are started and in which taskbars? What icons are there? Are there any special panels or menus? Do any other programs start automatically?
Describe how well the menus are configured in each window manager. Does each window manager have the same applications listed as the others, and are they laid out identically to the other supplied window managers as far as the window manager will allow? Are all the important installed applications listed? Are there submenus by category? If so, how well do the applications fit the assigned category? How many submenus do you need to navigate before you find what you want? Are there desktop icons for any applications? Do not assume that all applications shown in menus actually work or are even installed. For example, if the distribution includes a word processor in the menu, did you start it?
Discuss the applications that are installed in the distribution by category. Highlight any unusual applications. List any non-open-source applications. Note especially if anything is missing. For example, if this is a desktop distribution, are there office applications? If it is a server edition, are all the services available?
Discuss the codecs supplied with the distribution. How complete is the set of included codecs? Are all the free codecs included by default? Are there non-free codecs that might cause legal issues in some jurisdictions? How easy is it to get additional codecs if required? How well did the applications play the media you tested?
Customized control panel
Describe any customized control panels that come with the distribution. What tasks do they cover? How easy are they to find and use? Do the tools work completely or does the user need to do further work via non-customized tools?
Customized application configuration
Describe any customized application configuration tools provided. For example, is there a customized tool to configure encryption?
Describe any special programs and configurations not found in most other distributions. For example, if the distribution includes Wine, is it fully configured to run, and are there any installed Windows applications that are preconfigured? Are there icons or menu items that start these applications?
Describe the development tools provided. List the compilers, editors, and integrated development environments.
List the services that are started automatically. For example, is sshd started? Describe the system for controlling the starting and stopping of services. Is there an administration control panel for services? Are any important services not included in the control panel?
Describe the security features of the distribution. Is the root password weak or strong? Are there any guest accounts or does the distribution automatically log in as root? Are the guest accounts password protected? Does the distribution boot all the way to a desktop or is there a login screen? Are the passwords easy to find? For example, some distributions show the password on the login screen as part of the wallpaper. Are there special security features such as firewalls or automatically encrypted filesystems?
Discuss package management for the distribution. Test out some package installs. Which package repositories are preconfigured? How many packages are there for this distribution? What is the package manager? How easy was it to install applications? Did the newly installed packages work?
Describe the method provided by the distribution creators for patching the distribution. For example, are there any patches or does the user need to download a complete copy of the latest distribution? How easy is it to apply the patches?
Discuss the speed of the distribution if it differs significantly from other distributions. Does it boot extra quickly? Is the windowing system extremely responsive? Is the kernel optimized in any way that shows? Does the distribution run entirely within RAM? Did the install go extremely slow?
Describe the stability of the distribution. Do any of the applications crash? Does the distribution start the same every time? Does it have trouble with certain configurations of hardware such as laptops or old computers?
Describe what happens when the user exits. For example, if you shut down X via the Ctrl-Alt-Backspace key combination, do you return to a login screen or does the system shut down? Does it drop the user to a command line? Does the system power off automatically? Does it eject the CD during shutdown?
Discuss any tools provided for rebuilding the distribution. How easily can you remaster the distribution? Is there any documentation for this task?
Upgrade and rollback
Discuss the process of moving to a newer or older version of the distribution after having done an install. Are there any tools provided to assist with this?
List all the problems you encountered. Discuss what you found confusing. What did not work as documented? What workarounds did you have to apply? Did the solutions provided by the official support staff or the user community work? Are problems noted on the Web site, and does the project have an expected schedule of when they will be fixed?
Describe the documentation provided with the distribution. Are there man pages for every application? Is the info command included with full documentation? Does the distribution include the help files for each application? Are all the customized tools documented?
Describe the official support for the distribution. How responsive are the creators to user questions? Are they open to receiving help? How complete is the Web site, and how easy is it to find help there? Are there other help forums, such as IRC channels, and do developers frequent them?
Describe the user community to the extent you can judge from the distribution's forums. How large and active is it? How helpful is it? How friendly is it?
Source code availability
Describe the process of getting the software for the distribution. How easy is it to find all the software, especially for the customized tools? How well is it documented?
Releases and roadmap
Does the distribution have a regular release schedule? Is the schedule published? How closely do the creators adhere to the schedule? Describe the roadmap for the distribution. Are there documented plans for future releases? What things are in the roadmap?
Describe the history of the distribution. Has the distribution been stable at each release? How has the distribution changed over time? When did the distribution first appear and how often was it updated? Has the distribution been influential on other distributions or in other ways?
Provide useful screenshots, not just screenshots for the sake of having some pictures in your review. Useful screenshots mean noteworthy items described in the text, such as something that makes the distribution distinctive or anything particularly interesting.
Provide links in your review not only to the distribution Web site but also to anything that is not directly related to the distribution you are reviewing. For example, if you mention other distributions you should include links to them.
List the things you did not test and the reasons why you did not.
Your system and your perspective
Describe the hardware and software configuration of your test machine. Did you have any esoteric hardware? Did you run the distribution inside a virtual machine?
Describe your relevant experience. How long have you been using Linux? How many distributions have you tried? Which distributions do you regularly use? Are you an administrator or programmer?
Discuss your reasons for reviewing this distribution. For example, do you want to describe the latest release of this distribution? Do the distribution creators make any special claims for this release or this distribution? Have you been using this distribution for day-to-day work?
Disclose your biases. For example, do you prefer everything to be automated or would you rather have manual control? Do you have a favourite application that wasn't included when you thought it should be?
Summarize your review and your impressions. Compare this distribution against others of the same type. If the target audience is described by the creators, does the distribution meet the needs of the target audience? What kind of users will most like this distribution?
Consider having your review edited. Your review should be well-organized, clearly worded, and without grammar or spelling errors.
This guide on writing reviews means that you won't be able to blast through a distribution in 20 minutes, but the extra time you take to cover so many items will be rewarded by your readers' interest and appreciation. They'll want to read the next thing you write. Your review may become the definitive standard against which all others are compared.