I decided to rent this game tonight. It was a tough choice between Wario, Boom Blox, Samba de, and this game. I went with this one because I'll probably pick up Wario and Boom Blox for Christmas, but wasn't sure about this one. I'll start playing once I get offline.
On a side note, I don't think I'll be renting games for a long time. I didn't realize it costs almost $10 to rent a game from Blockbuster. It's a bummer, since I really want to try Wii Music without having to buy it.
*Edited in a few hours later...*
This game has exceeded most of my expectations. It's just so much fun to play. There are a few frustrations here and there, such as camera and the jumping being a bit frustrating. But while playing it, I keep flashing back to Jet Set Radio, and that's a good thing. The gameplay, music, and total package is solid. Overall, it's worth a purchase, and I think Nick's review of the game is spot on.