I've been making edits to both my address book and iCal lists, as well as adding new photos to my address book from both the iPhone end and my iMac desktop, and so far it appears that every sync has worked in both directions.
The only strange thing that happened the first few days was that when I set the iPhone in the charger, iPhoto would often launch (to sync pics) but iTunes would not. If I launched iTunes manually, my iPhone would then show up on iTunes and all syncs would take place.
Today, however, iTunes launched right away and did the job.
Gremlins I tell ya!
😉