Naagza, I said the 3DS version is better, but I can be 100% sure because I didn't played the Wii U counterpart because I don't have the Wii U.
In the case of Sonic Lost World, I made a review here:
http://3dspedia.com/sonic-lost-world-3ds-review/
I can only said there is more replay value I found after making the review, but in the first run in some levels you will get some frustrated.
Without experience, this game is hard as hell.
What this means?
When you start to play, lifes are treasure.
When you finish the game and start completing the game (S ranks, red starts, play extra levels and hard mode) life are really easy to keep.
In my opinion is harder than Sonic Adventure 2.