Yes I have one as does my director.
Few problems in the car.
First this seems to be a WM6 issue, so guessing will affect any PDA running WM6
1. My Z4 I have a parrot kit which is tempermental, sometimes when the phone connects the parrot displays "call" and mutes the radio. If you make a call from the phone to say your voicemail it corrects the system and all works as it should thereafter.
2. Director has a 535d Sport 2004 model fully loaded so using BMW bluetooth. Same issue as above, sometimes it picks up his other phone which has a lower priority. He also get crackles and other noises when he starts making calls etc.
We both had http://www.myqtek.com/europe/products/9100.aspx and these worked perfectly in both cars and my old 2005 3 series with BMW bluetooth.
As I say it is I believe a WM6 Problem.
Also different note there is no Remote desktop facility which is a real PITA as I cannot connect to my servers easily now.
But other than that it is a cracking phone with built in TomTom6, GPS, Business Card Scanner, good keyboard, and so on....