I'm in metro kingdom now, doing lots of side moons along the story line, but not too much. Trying to buy every region specific outfit. Wonderful game, pure Nintendo magic.
Still have to get a full grip of the controls, despite playing all previous 3D Marios loads of times. Many new moves and slightly different walking behavior. Really missing the in-the-air swirl-jump from the Galaxy games, but I think I will develop an alternative as I play more.
Grafics sweet and beautiful, a little step up from 3D world in terms of quality, still has no anti-aliasing tho and the jagged edges do get noticed. Have to sit further away from TV