I think it's the Wii U hands down, Nintendo as they often do really think about the practical uses of the device and then build the functionality to match. The most impressive feature would be the remote play on the screen from the other machine. I think it will be exactly what people want, I know it is a problem I sometime face wanting to continue playing games when others want to watch a program.
The Vita to me just looks like Sony have tried to copy a few smart phone features but haven't thought why, I definitely don't want touch screen to make a character jump from one side to the other even in the video it looks annoying and would get in the way of good game play. The example of having a curser for little big planet again doesn't seem necessary I already have analogue sticks and could use them or a button, this would just slow me down while playing a level.
I do wonder how much player market research was taken before they made the Vita because they don't seem to have made something they are entirely sure about. If you have these features you have just spent vast amounts of money investing in, surely you would have a clear goal of why? I can't believe that levitating golf players was on the top list of reasons for having touch screen on the back, so how come this is in the trailer? Looks like they built the feature but no one asked why.