After a couple of weeks using the iPhone I have to say I am very pleased.
I have had no problem with pairing at all. It pairs right up with all four cars - one with iDrive, one without, and two with aftermarket Alpine units (9847 and 9885). Sound quality is fine. The only glitch is you have to remember to disable WiFi when using the BT in the car or else you get very choppy audio during phone calls.
When connected the iPhone charges in each car. I normally use an iPod for audio and keep the iPhone out in the center console. If I need to charge I use the Monster charger plugged into the center console.
My iPhone synced up perfectly with Outlook for my contacts, and all of them display perfectly.
The iPhone's iPod plays through the speakers and sounds excellent. All tracks/podcasts/playlists work normally. I had one instance with my 1992 325i's Alpine 9885 where the audio came from the iPhone and not the stereo. The problem was resolved by turning off the car, connecting the iPhone with the car off, then powering up/starting the car. It has not happened again. Make sure the 30 pin connector is seated well.
Voicemail has to be accessed the old fashioned way as discussed earlier in this thread. Visual voicemail is great, but listening to messages as we have in the past through a BT enabled audio system is hardly a problem. Pull over and take a break if you need to use the visual voicemail.
I have not had the chance to see how the iPhone behaves with Call Waiting. Anybody had any success handling two calls with the iPhone connected to BT?