i've played it twice... at TGS / Hudson's dev studio, and a gamer event here in san fran. embarrassingly, i have yet to finish and post my full impressions, and here the damn game is already released!
bottom line: the controls--like any racing game--take some practice to get used to, but after only 2-3 races i was coming in first against other players and the CPU. balance board wasn't available for testing, neither was online versus. it's a little odd, weapons and snowboarding, but it works. kind of like downhill F-Zero or Wipeout. add in some customisation; sure, it's worth 10 bucks if you have some cash to spare and like games like this. if it'll burn your entire wii allowance, i'd maybe hold off to get some concrete reviews and plenty of video footage.
if i can snag a review "copy", i'll expand my thoughts for ya.