Biggest differences between the Sharp 2.x and 3.x ROMs:
1. PIM data file formats changed: 2.x ROM PIMs store data in XML, 3.x in the proprietary DTM database format. This leads to more stable syncs between PC and Zaurus, but there currently is no direct sync between DTM format and Linux boxes (only Outlook or QtopiaDesktop on Windows).
2. Everything on 2.x ROMs ran as user root; on 3.x ROMs, most things (especially those launched from Qtopia) run as non-priv user zaurus. This can cause some programs to break, due to permissions issues.
3. Some applications that were considered a possible security risk (ex: FTP server) are no longer installed/enabled by default on the 3.x ROM.
4. Qtopia launcher no longer sees every file installed on SD or CF card. While this is generally a good thing (there were workarounds for 2.x ROM), you lose Categorization in the File Manager.
5. UI customization is better in 3.x
Even with the above noted limitations, I find the 3.10 ROM to be quite stable & suitable for my every day needs as a PDA+.
