I had a problem resyncing when I went to 2.0.
No idea why, but I synced in 1.1.4 then pwned fine to 2.0 and everything worked great. Resynced but upon reboot the iPhoen got stuck on the Apple logo with the 'cog' wheel spinning over the top - it never made it to the springboard on the phone although iTunes would recognised it as connected fine. In the end, I re-pwned and didn't sync - just copied the .db files for notes and SMS over manually and resynced contacts from new.
A few hours later, just didn't like the App store offerings (crippled weDict which is very important for me to have multiple dictionaries and a thesaurus), plus other programs I need and miss from installer that are free (Sketches, iChinese, fring, iStudy, VideoRecorder, ruBooks, etc, etc). Decided to go back to 1.1.4 and give the app store 6 months to settle down.