I've been a Palm/Mac user for about ten years, and I recently purchased a BB Curve. I'm using Pocket Mac to sync the BB with iCal and despite a few quirky connection issues (from reading the forums they will hopefully be cleared up in the next release) I haven't had any major problems. I enter all of my appointments on the BB and overwrite the calendar. If you plan on using The Missing Sync you should have no problems syncing with address book and iCal.
I've been extremely happy with the stability of the BB compared to the Palm OS. The transition to using the BB calendar and ToDos went fairly smoothly, it took me a while to get used to the lack of colour coded entries in the calendar but that's all I miss.
I've found the call quality to be very good, and I'm happy with the SMS functionality.