Honestly, if you like Mario games, you should probably just play 2010's Super Mario Galaxy 2. It's basically the best 3D platformer ever made, and it knocks the socks off of the other Mario games.
I'd have to disagree. The level format felt far too linear compared to the original SMG, Super Mario 64, and especially Super Mario Sunshine (a terribly underrated game which barely gave you a set path to follow). Kind of a weak soundtrack compared to the first SMG, too. The best 2D platformer is still Super Mario World thanks to all the secret exits and the fact that Mario has a goddamn cape. Bonus points for all the awesome ROM hacks done of Super Mario World, too.