Thinking of either of these for DS's 4th birthday. He has trouble on my ipad staying in his folder and I've tried all sorts of ways to keep him out of my stuff but nothing works so far. If there was just an app that could lock in one folder that would work maybe. Anyway I thought maybe one of these would give him the freedom he needs. I know the games are quite expensive compared to regular apps but other than a cheapie tablet is there anything better? The LeapPad 3 is $99 and the XDI Ultra $149. Thoughts and experiences would be appreciated.