The Happ style switches are great, super good response and they look awesome too.
A few notes, if you are going from the OEM buttons you'll either need to stretch the terminals out to fit the Happ connector or buy the .187 jumper wires they sell. I'd recommend the latter as part of the purchase. The Happ style buttons have 3 terminals, one on the side and then two on the bottom. I used their jumpers and attached the blue cable on the side, then connected the white cable to the one on the bottom closest to it.
https://www.diyretroarcade.com/collections/a1u-34-encoders/products/zero-delay-usb-encoder-jumper-wires-terminals-size-0-187-compatible-with-happs-style-arcade
The buttons don't come put together but they are pretty easy to figure out. The LED lights are a bit of trial and error for positive or negative connections in my experience, if you get the added terminals and barrel connector for power.
The team was very helpful with any questions via email.