The Wii-U isn't something I'd touch. That's pretty telling for a Nintendo product, given that I've owned most of the things they've pumped out over the years and been pretty happy with them.
The "screen" controllers are too expensive (the backward compatibility might be there in some games but there's no real guarantee of that, and thus it's much more expensive that the Wii was for many years in comparison). The Mario game is too much about having two half-decent players trying to do everything on the same screen (which is not the thing to do in the casual market, because it either gets crowded, or you have to suffer fools, quite a lot). And I haven't seen much else that actually entices (about the only other thing I've stumbled across is that zombie game, and that's just NOT something that anyone who owns a Wii for casual gaming will rush out to buy - wrong genre, too much stress on quick action, etc. from what I saw).
As such, I honestly haven't even looked at it in a shop. I have a Wii, it does for what I bought it for (quick, cheap console to plonk a child in front of, or to bring out at random dinner parties where random adults - mostly non-gamers - just want to bowl a few balls on something they understand even if they never game). I don't see the point of the Wii-U.
Can I even transfer my store games from Wii to Wii-U? How does that work? Do I have to abandon the games I bought on the store for the Wii?
Personally, I think Nintendo would have made a lot more money with a Wii (or Wii upgrade) that allowed multiple Wii-Fits, had HD graphics and let you use an Android / iPhone app to turn them into additional controllers (or even screens, maybe) over Bluetooth (though that would have hit their controller sales, it would have made the console much more appealing, especially in the "we need one more controller for everyone to be able to play" scenario).
I didn't "get" the Wii-U. I owned a Gameboy, a SNES, an N64, a Gamecube, and a Wii. But I don't "get" the Wii-U at all.