My bad! Yes, it looks like WiiFitU will be at least a full year ahead of WiiFit on the console timeline. I find it interesting that Nintendo is moving up to of it's massive sellers NSMB and Fit, to earlier in the console life cycle this time around. I wonder if this is a good or bad decision.

my kids love wii fit for some reason but with wii fit u and how you can have it to where it displays your personal info on the gamepad instead of the tv screen is a huge plus. i think once the wii u starts rolling its going to be flying off the shelves as it is. my guess is by end of 2013 price drop of the cheaper model to 250 and it will start selling very well. 

I think Wii Fit U will be a big flop. But it is just my thought.

the only thing i'm certain of it it will be "supply constraint" for years to come regardless of how well or bad it sells..

The only real competition for Wii Fit U comes from Wii Fit Plus, as the game is so much different than everything else in the market. The question remains if Wii Fit Plus performs the job well enough for gamers, or does Wii Fit U solve problems seen with Wii Fit Plus.

In any case, the gamepad is a huge benefit for the game, just like dancesteps. It would also be a great addition if it would feature online.

As for the sales, as a "safe bet" I would guess 75% of the sales of the original, however I could see it topping 25M if things are done correctly.