I would simply like to concur with Rockman.
It is easily on par if not better than MKDS and the control scheme is very well done as far as using the Wii Wheel goes, I'm a bit pissy that GC and Classic controllers can't perform certain things that using the wheel can, but aside from that it is amazing fun on single player and I'm looking forward to trying it out online.
Oh and level design is by far the best since MK64
i also agree, its great game with some much needed improvements. Although i do hate a couple of things:
-Battle mode online is awesome, but it is only teambased and when you die you come back to life and the other team gets the point. While this seems like an improvement, it really is not due to the lack of voice chat and the fact that most people like me are used to the old way.
-I mentioned it above, but there is no way of communicaiting with comrades. Sure most nintendo games are like this, but medal of honor 2 heroes allowed you to send messages to friends when not in-game. Hell, even brawl had the taunt system but atleast that was a form of communication.
-Most items are awesome but i hate most of them. I mostly hate the blooper item though for good reason. Instead of getting the player that is a place in front of you, it gets everyone and it can be a real pain in the ass if everyone but one person is driving aimlessly around the track. Also the unlucky leader could get hit by a koopa/spiny shell which would make it seem like a cheap shot.
Otherwise I think it is a fantastic addition to the HUGE mario universe.