I used a full size iPad 3 with Foreflight. I didn't have a mount, just had it on the seat beside me when solo, or my wife held it when she was on board.
Now use iPad mini, initially dithered over making the move to the mini thinking it may be too small with the sectional displayed on it, but having flown with a friend and sampled it first hand in the cockpit, I was sold on it, don't really feel the size is of any issue, added plus with the mini, I now have it secured on a knee mount.
Full size iPad is still on board along with my paper charts just in case I lose the mini or the panel GPS.
No overheating issues with either version, and my flying is mainly in the heat and humidity of Florida.