Before anyone jumps on this, I want to share something.
After playing Melee competitively for a couple of years (along with a couple other factors), my boyfriend started getting severe hand and arm cramps, and it eventually led to him developing carpal tunnel-like syndrome on his triceps. Now he can't play Melee anymore without risking injuring himself further.
This controller actually gives him a way to play Melee again without that risk. He has been all over it since it was revealed from a while back. And, according to him, mastering this controller can actually lead to more technical play due to the instantaneous button inputs.
So what I'm trying to say here is to just give it a chance. I too am skeptical, but he's more familiar with Melee than I ever will be, so I trust his word on this.