I just received my new Phantom 2 from B&H (I also own a Phantom 2 Vision). Perfect out of the box. Some observations about calibration. After connecting to the Assistant software and calibrating, I went outside to calibrate the compass. I calibrated it about 5 feet high from my back yard cement slab and within reach (possibly) of the Wi-Fi signal from the house. I tested it and, although hovering fine, it tended to drift left and forward. Tried again and same thing. Then took it to the front of the house quite a distance and over grass and calibrated the compass again. This time it hover perfectly with no drift and flew perfect.
Lesson learned, never calibrate in areas that may have metal (even patios or sidewalks or where Wi-Fi signal may be present. Even if you are going to fly over a patio or cement, try to calibrate the compass away from any interference. I also tried the same with my Phantom 2 Vision, and noticed same results. Hope this helps.
By the way, this controller came with the USB port outside, not inside like in the Vision.