For what reason should I buy a Classic Controller? What benefits does it have over Gamecube one? And vice-versa?
Beer is proof that God loves us and wants us to be happy- Benjamin Franklin
Compatibility and personal preference. Some games and programs only support one of them and not the other. Seeing as how both aren't necessarily supported all the time it's not a bad idea to have both...I have 4 of each. When both are supported it comes down to which one feels more comfortable to you.