There is a clear issue when it comes to shooting 4K video on the Xperia Z2, and that's a real shame as it's capable of producing quality footage.
The heat sync issue coupled with "unknown error" crashes smacks of a handset which hasn't been tested thoroughly, and the slow image processing times see it lag behind the competition.
I'm not a huge fan of the bezel heavy design Sony has implemented either, and it makes the Xperia Z2 look a little overbearing in the hand.