Bought to replace worn out controllers and they work great. Haven't noticed any discernable difference when playing smash bros
I bought this controller for it's shell planning on swapping it with a new official Smash Ultimate controller's shell (1st party interiors, 3rd party exterior).
The color of this controlling is absolutely amazing! It's very close to the N64 Ice Blue controller color, but maybe a little more towards a turquoise color. Either way, the texture on the shell feels good in the hands and the shell looks great.
The one downside of the controller is the location of the slot for the z button. The shell IS usable over 1st party GameCube controllers (you do need to remove some plastic in the back of the bottom shell, but this is common for 3rd party controllers and is fairly easy to do). However, the hole for the z button is ever so slightly off from where its supposed to be, meaning that you can't mix shells with first party shells. I also am concerned if that may cause damage to the interior/more specifically the z switch, but I am not positive and won't really be able to know until the controller gets some use.
I would love to buy a bunch more of these shells for more controller projects if they update the mold at some point to address the z button issue. That being said, these are still very solid options to reskin your controllers and they look great.