Wii U is great and i love the games with it. Also bought some 3rd party games and would play them as well but currently playing MK8 with my daughter and wife to have blast. My wife is now a little bit competitive and learns the drift and other controls. she may nick a win or so but that's about it. And I figure out that computer AI tends to be great if the human playing MK is really good. When me and my wife are playing with the AIs, there are times they are really really fast and competitive even on 50cc. When we tried to play with our daughter and wait for our daughter, the AIs tend to leverage on the slowness of the human player and still a good race. When my daughter is playing alone on 50cc she can win 1st place and AI isn't that competitive. not sure how they translate it in the game but it seems AI tends to check the speed of the human players too.
another thing to note, now i know why younger gamers who own Wii U has its top software as Netflix and Youtube. My daughter loves watching in the gamepad or so, and said, "daddy this is awesome". since they came here for 2 months and i can't play Xenoblade at the moment. Once the kids go back and go to school, then I'll be alone with my consoles and start getting those big hours playing with my Wii U and othe consoles.
