Issues I've had...
1) POP e-mail doesn't show up in std mail tool. Files are still on card, but new mail isn't getting stored there. Can't figure out how to tell the mail tool to put stuff on the SD card
2) Standard browser tends to crash, mostly after a re-boot of the phone. After a couple crashes, it seems OK. Reset it to stock (browser only), and crossing my fingers.
It does delete you contacts, but to be fair, it does tell you that! So just synch them. Also had to rebuild the screens, but who cares. Except for the two issues above, I've had no other problems yet. All apps are there and working. Phone is noticeably snappier compared to 1.5. Navigation works VERY well! Tried it this past weekend, and it was spot on. I've been waiting since day one for that, so I'm happy now. That's one of the things I wanted on the phone, so no way will I go back to 1.5.
Don't want to do a full factory reset, because some have reported problems with that.