Bluetooth setup with my Droid2 (Verizon) has never been a problem. When I'm in the car, incoming calls are received perfectly, and calls that I make through the phone itself are immediately picked up by the vehicle's bluetooth.
Placing hands-free calls, though, is sketchy. The most frequently occurring problem is an inability to complete a call the voice recognition/hands free system initiates. I hear it "dialing" but, after about 5 seconds, the speedometer console advises me the dialup failed. If I repeat the process, the call goes through successfully.
All told, this happens about 50% of the time.
With the support and assistance of VW of America, my bluetooth unit was replaced. The problem recurred.
I tested the bluetooth setup with an old, "basic" phone and everything is rock solid. The difficulty seems specific to the Droid 2 (with the latest Android system, 2.38 (I believe)).