I had an iPhone 3Gs from the day it came out until about a month ago, in my G37s. The only problem I had, was that I couldn't transfer the phone book. The voice quality through the speakers was fine, and the voice going out is also fine, according to the people I talk to most. When I started the car, the iPhone always automatically connected via bluetooth. If I remember correctly, the caller ID didn't work, unless I had the number stored in the phone book in the NAV.

About a month ago, I got a Droid, and it works exactly the same, right down to the caller ID not working. Again, as far as sound quality, it was just fine.

I think you'll be fine. Unless my iPhone or G are special in some way.

 

I have a droid and iphone and I have seen the exact same results. The only thing that will not work, like he noted, is you cannot download the phonebook via bluetooth

 

I have a 3gs and I have to say it is fine, no problems with calls being dropped any more than they normally do from ATT. And as everyone has said, just can't put in phonebook. However, I don't have many friends so it was easy to put in a few people I actually call