I'm absolutely in love with this game, started playing it last night and I couldn't put my controller down - I love how they have the old retro things in there such as the pow blocks. I like the RPG faction of it, makes for very interesting playing for a mario game, and the flipping from 2D to 3D to find secret ways/items is a lot of fun.
Biggest love though - when you pick up a star, and you end up breaking everything as a giant retro mario - sooo much fun