There is way too much hate for the GC controller. Out of the 3 I thought it best. Having lots of face buttons, with the same shape is way too difficult. I loved the A, B and kidney system. It worked really well. I would say the D pad was not good.
In the PS2 controller, I didn't like having 4 shoulder buttons. I didn't know whether to put my index and middle fingers at the back or just the index. If I put both I found I wasn't holding the controller firmly, and put too much strain on the pinky and other finger. Hence why I like the idea of only one side with 2 shoulder buttons. The other hand could hold the controller firmly. Also the ergonomics of GC was the best.
In conclusion, the d-pad was the only let down. PS - I didn't really buy many ports or 3rd party games, so maybe a lot of you have a point, but then again, that's nothing to do with a poor controller, more like a lazy dev.