One of the best things from a metadistribution like Gentoo is its approach to upgrades and management
I've started using UNIX systems with Minix and Xenix, in '92-'93 I was rolling my Slackware distro with a brand new kernel called Linux, nobody knows it but it was fine and I was happy with it, never tried other Unices and neither worked with others. After a short period I've started on working with UNIX systems heavily and I've seen a lot of them, one of the biggest complaints were the system upgrades... oh what a mess.
While using Microsoft operating systems, upgrades were not even considered but after facing UNIX and some development movement due to Linux grow I was thinking upgrades are one of the most important parts of an entire system, one of my biggest concerns was:
"ok now I've a full upgraded/stable/configured system, it was a pain to get everything working but now it's fine, how can i maintain it stable forever ?"
Each time a major release came out configuration and reinstallation problems were the most common
After few years, I think '94-'95 I've tried something from the BSD world, I didn't remember what (think OpenBSD), one of my biggest problems there was: "where are my applications ? how can I install packages ?". Hell there weren't available in my system CD and I was searching for them across the net; after few good docs I've learned about package distribution and how my system can handle upgrades, it was a revelation to see source code packages (builds), download the source, auto-patch, compile and then install. The best thing I've ever seen and I was thinking something like: "oh damn, I wish to have something like this for Linux as well".
After it I've started using Linux from scratch approach (LSB), it was nice but each "major" upgrade was still a pain and I still need to patch and control everything by hand... since a day, a strange day, I was googling around and I saw the latest distribution of the day, it was called Gentoo. I've learned about Gentoo because one of the lead BSD developers ported its experience to Linux, I was following BSD (still I'm on it) and learned about this new distro.
I've tried it for a while and I was so impressed about portage and meta-packages, so I've decided to use it as my Main distro (I'm writing this blog from a Gentoo desktop system). Other features like code optimization and C compiler flags scared me for a while but now I'm fine and I can live with them
Here's how I've approached Gentoo, still using it since a lot of time and still happy with it