Somehow iTunes stopped syncing by iPhone with no good reason for. No error, nothing. It just ignores any changes in the Address Book and iCal, until I'll click on Selected Calendars and back to All Calendars. Pretty often it works after that. However, sometimes you've to do this more then two times. I think resetting the Sync history in iSync could do the same thing, but it adds even more headache.
Actually, I'm getting more and more concerned about my iPhone (I actually have an old one 2G version, which is unlocked for T-Mobile). It's pretty dumb when I'm trying to use Maps & Safari & Mail, switching between them at the same time, and all goes over EDGE (actually, I found GPRS sometimes to be a little bit faster, which is ideologically wrong). I'm running 2.1 firmware though. I think that 1.x versions were way faster.
I don't know much about new 3Gs, but I didn't heard anything good about them either. ;) I'm leaning more towards the good old Nokia N95 (or maybe N96?), which ocassionally can be found new & unlocked for $299. My Nokia experience was very good, but I also heard nice things about Blackberries (never owned one, though).
Beeing an Apple bigot (and I acknowledge this) I wish I had a better experience with iPhone. While I have it since the first release, it's a long lasting one. But I find it to be too slow for active use (something, but the iPod or placing calls, but modern phones aren't about calls anymore, right?).