I just got it today, and overall I love it. It appears to have fewer tracks than the DS version, but I haven't counted them yet. As MSD said, it seems like the AI no longer lets you get more than 1/4-1/2 of a lap ahead before dropping the hammer on you.
In all it seems to be well balanced, I'll see how it fares in a multi-player environment at my move-out party this week. Drunken MK for everyone
Oh, my friend code is 3308-5453-0269