I'm really enojoying this title. Best Mario since World and SMB3. They perfected the controls and level design. I don't think they can make it any more better with the NSMB formula. Its perfect, really.
What I really am enjoying at the moment is playing this coop with my girlfriend. She is not a skilled gamer and isn't really good at Mario but the boostmode Gamepad Wiimote combo makes for some brilliant multiplayer gaming. It makes this console a true social experience, which I have been missing even in the Wii. Its fun to experiment what kind of effect tapping stuff has in the game, its not only placing blocks, but also disrupting enemies, finding secret exits and stopping projectiles. Its still challenging, even in boostmode, and that is fine. The fact that casual players can jump in and have as much fun as you is brilliant. I would really love to see a Zelda with this type of coop.
The future is bright for the WiiU.