Well I really had my hopes up for this phone, and dumped my iPhone 5 for it... now I regret it, the phone freezes almost everyday it froze the 2nd day I bought it while I was talking through a Bluetooth headset, the day after that it froze while switching between calls... and today it also froze while I was talking through my car's Bluetooth set... I don't know what's the problem with this phone and also the camera is not that good and doesn't deserve all that hype. Nokia & Microsoft you'd better fix these issues because although the Lumia 920 has many good features, I can't stand it for this regularly freezing.
P.S. I'm currently in Saudi Arabia and the Nokia Care staff here are totally useless, shame on you Nokia you should've hired a qualified staff at least.
I've had the Lumia 920 for 2 days. Twice today, it froze up and was completely unresponsive. In both instances, it was directly following a phonecall using my cars bluetooth connection. The call was completed, I hit the "end call" on my steering wheel, and then the phone froze up. Same issue twice. either its a bluetooth glitch in Nokia or I have a bad handset? Love the phone otherwise, but may have to revert back to iOS if this keeps up.