I recommend it whole-hearthedly. It's the best Mario Kart yet. It requires skill, but you won't get the same place every time, even if that is the place you "belong". Online is great, and running against other people's ghosts is simply awesome. In my opinion, Mario Kart Wii might just be the best online game yet to reach Europe.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS