This game is Ace! Couple of wee bugs (pardon the accidental pun) but otherwise awsome!
One thing though, you are right about it being short. I completed it with 5 hours of gameplay and I'm not a hardcore gamer. If they continue with titles like this the future for Wii looks brighter.
I purchased it about an hour or so ago, and it's a very solid title. There are some framerate issues somewhat, but it's tolerable. Graphics are really quite nice, to Wii's standards, and the gameplay is pretty good. So far, I'd say it's about worth the $50.
Support good 3rd party games people!