3D Mario .... hook it to my veins. I hope they let you download the demos at home for people who already have the system, but I'm guessing Nintendo is going to get some kind of favorable deal with Best Buy (store shelf or promotional stuff) for doing this as I have to imagine Best Buy is quite happy with having people forced into their store to try out the demos. Oh well.
I understand it's a good choice for people who don't own a Wii U and want to try out the future games.