The new ROM is supposed to fix most of the problems that users had with the original (V 2.x) ROMS the SL-5500 was shipped with.
There is, however, one major drawback: there's no new Linux version of the Qtopia Desktop software yet, that'll probably take another couple of days."
According to the Sharp developer forum zhe New ROM contains the following fixes and changes:
Faster and improved synchronization
Synchronization of eMail attachments
Updated Email client with separate folders for each account
Opera 6.0 browser
Updated Address Book with user configurable column headings
Updated Calendar with additional new views and improved support for all-day and multi-day events
New Zaurus File Transfer with simple drag-and-drop file movement
Integrated File manager (replaces Documents Tab)
Extended MP3 playback with display off feature
Backup/Restore the Zaurus with your PC
Intellisync Version: 3.2E
Qtopia Desktop Version: 1.5.4"