If you have several friends with GBAs and link cables, then go for it.

The single player mode... I had fun with it. Moreso than the average person, I think. The average response seems to be "The single player mode isn't mind-blowingly awesome, but it's enjoyable."

Should you get a GCN just for this game? Probably not. You should get a GCN for all the other spiffy games, with CC as a tasty side dish.