I have owned my Nexus for 3 weeks now. I have experienced my Nexus just shutting off for no reason. It has not been doing the same thing. Once I was setting up pictures to my contacts, another was looking through the Marketplace and lastly once when I was downloading an app. Did not wnat to turn back on right away. Had to hold the power button longer than normal to turn back on. I have also experienced issues when playing Angry Birds, it would not let me out of the game. There was no back button, no Home button. It would not show up. Only had a cascading option. Had to turn off the phone and wait a few minutes and turn back on.