All said, It's and "Ok" 6.5 - 7.5 game.
The online play is nice, considering some other games that need friend codes and the like. But the online is also dissapointing because of its matchmaking. When I was just starting out, and at a rank of X or Y, the wifi matched me up with all expert players (including a C!).
SFC does easily allow you acsess to play with your friends through one card, which, if you can find a friend or two willing to play, can be fun.
All said, I wouldn't pay much more than $15 (US) for Star Fox Command, as I really only use it for the online wifi play