For me:
GC>XBOX>PS2 controller.
same order this gen. The only thing I didn't like about the GC controller was the C-stick. I absolutely loved the trigger buttons.
I also like how the analog stick doesn't have completely round outlines. It's easier to point it in the four directions since they have groves in them. I always had problems using the PS2 analog stick because it's low placement + a round outline. I never could tilt it straight up when I wanted to.