My 2 cents....
I installed this a few days ago and love everything BUT the bluetooth, which was one of the main reasons for getting this. I have had factory systems in a nissan maxima, and now in my wife's bmw, and they both worked/work awesome. I currently drive an armada and use an iphone.....(For reference of course)
I gave my wife a call and she said it was horrible. I could hear her fine, but she could hardly understand me. I located my mic in the center overhead console, just like the factory installs on our other vehicles.
I wanted to hear for myself, so i called the house and listed to myself on the answering machine. Yep, I could hardly understand myself. I pulled the mic out, and was using it at all different locations, in front, above, even 1 inch from my mouth and it remained the same 
I then tried it with the engine off... It sounded PERFECT!
Also, it didnt matter where the microhone was located, it sounded nearly the same, didnt matter if i was 1 inch away, or 3 feet away. As long as the engine is off, I must say, I sound awesome!
The only problem, THE ENGINE HAS TO BE OFF!!!!
I can't believe it!
Does anyone have any ideas how to fix this?