Quoted from winteriscoming:

Anyone playing it multi-player?
I'm not enjoying multi-player as much as I had hoped. That alone lowers it from a perfect score for me. I don't know. Maybe I went into it with the wrong expectations of a robust 2-player experience. After playing as the hat last night, I just found myself frustrated trying to direct my wife where to go with Mario. I might as well just watch her play. A few times I tried directing the camera and she walked Mario right off a cliff...
Super Mario 3D World had some good multi-player, but was way too easy.
The best multi-player Mario seems to be the New Super Mario Bros series.