I use the Motorola V600 with a great deal of luck. The radio (GSM and Bluetooth) is the best I've ever used... I NEVER drop a call in areas where dropped calls were common with different GSM phones.
The limitation of the Moto line is that address book. On the phone, you can enter a "type" of phone number (mobile, home, office, etc). This information isn't stored as text which is usable by the BT connected address book so if you have a name with multiple numbers, they all show up looking the same on your Nav Display/Radio (you can't tell which number is someone's home office or mobile number).
The diaplay on the BT Address Book is also limited in the number of characters it will display for each address book entry.
I have worked around these limitations by appending the type of phone number to the end of the name, and shortening the names... e.g., The entry called "John Smith" and tagged with the "mobile" entry became "jsmith - m" in my Moto Address Book... and that shows up great on my car, and is easy to know whom I am dialing.
Hope that helps!