the shape of it is perfect, although quite ugly. It shows Nintendo designed it for function and not form, unlike sony.
The only things i dont like are the X and Y buttons, they're too hard to differentiate with on screen instruction and even by feel and the little z button is so easy to forget even exists.
I do like the way the analogue L+R have the click at the bottom of the press.
The big green A and smaller red B is a great idea, makes i obvious which is 'yes and no' but it may have been better to incorporate the snes diamond with that, instead of the X and Y.