I've bought 3 of these. I also own an Alpine deck; for the money, the MEX-BT3900 rocks. Also, I wish the radio preset buttons were completely separate from other buttons so I could more easilly hit the station of choice by feel. So for now I still take...
Easy to set up with my Droid. Decent eq options. Fiarly powerful amp (52Watts/ch), separate amp outputs for 4 channels plus sub. Mic in
Built in mic is on the faceplate and works ok, but if your car has a lot of road noise (on the freeway) or if you have your heat/air on high, it will be hard for the other party to hear you. Best to get a decent mic and run it to your visor, etc