Wonderful 101's a fun game, though I don't think the demo completely represents how the actual game is. The difficulty ramps up, and sometimes has an unfair spike in difficulty. Just letting you know. If you enjoy a difficult game, then that isn't a problem.
Meanwhile, WW vs Pikmin 3 is kind of an apples oranges argument. I don't really think you can go wrong though. --- Not changing this signature until a new F-Zero is announced. *started 6/18/10* F-Zero > Mario Kart. If you disagree, it's because you're bad at F-Zero.