Okay i recently beat this game for the Wii U. It is everything a Mario should be. It has really nice graphics, and is a breath of fresh air with new suits and Yoshi....and not to mention Baby Yoshi.
The story is the same as always: Peach is kidnapped by Bowswer......and his fam. Out of all of Bowser's kids u face off against baby bowser the most.
The game has air tight controls and has multiplayer playthrough...but i can imagine having 3-4 players at once can be tough. The game gets really difficult later on, but with perseverance(and power ups sometimes) you can beat it. The games final showdown features a run to bowser with Baby Bowser on your heals....then u fight Bowswer the old school way. AFter that things get crazy.
Overall I'd give this game a 9.0/10. Its not perfect but its one of the better games i've played period.