I picked this controller up so I could have four player gaming sessions on my Wii, but I wished that I had just payed a little extra for an official controller. While it looks identical, minus saying "NINTENDO GAMECUBE" on the front and the Nintendo logo on the back, all the buttons feel wrong. The left trigger needs less pressure than the right trigger, and the rest of the buttons are far to clicky. It's quite different than a normal controller.
Also, the wire is shorter and thinner than normal gamecube controllers, which is a pain because the 4th controller port on the Wii is quite far back, so whoever is using it needs to sit close to the T.V.
Maybe I'm just being a snob, but I thought anyone thinking of buying this should know that if you have used official controllers, this will feel off. If you don't really care it works fine, but I'd say it's worth a little more to get a nice one.