After a few hours with the game I find it to be a straightforward, no-nonsense update of the classic.
It retains the play control and 2D aesthetic of the classic, the track edit modes are simple and intuitive (and unlike the original cartridge you can actually save your tracks now) and the online multiplayer is icing on the cake.
Glad to see Nintendo take such a dead-on approach to both updating a classic AND delivering a great WiiWare title.
This should be a $10 no-brainer for fans of the original.