It definitely does not affect gameplay. The ONLY issue I had with the stick is that my N64-USB device isn't 100% on point with the reaction time. But on the N64 its spot on 100% reaction time.
And its no smaller than the gamecube stick.
Oh crap.

Irvgotti, exactly what USB device are you talking about? Is it a 64port-to-USB converter, or is it a modified 64 controller that goes direct to USB? I have a converter (
this one to be exact) that I use for the infrequent emulation that I do. Is that what you are talking about that is affecting gameplay?
I just installed all of these sticks into all of my 64 controllers and threw the original sticks away. I hope I didn't make an oopsie on that one...
Also, to mariocaseman, just give it a shot. It literally takes two minutes to install one, and unless you had troubles playing Gamecube games and you thought their controllers were God-awful (which I can't imagine either one being true), then I'm sure you'll find that you like the new sticks. And I'm confident they'll hold up through time better than the originals.