Hello, first time I post here, but I've done a lot of modding on the Zero for a year or so and followed the boards here. I've done the Gameboy D-pad mod, with also the extra pad under the membrane. The extra pad is what made the controls perfect I think.
Now I tried the new buttons and D-pad (all red), and I understand some of the complains here. They are good but not perfect. Lacks a little precision. And I think placing a 1 or 2mm pad under the membrane is what is missing for the D-pads controls to be perfect. Still have to test that out with new D-pad though, but I'm pretty sure that it will be as good as it can be.
Now regarding the 4 buttons, they are a bit better but still not good enough. The problem I think is that they are too small and/or too close to each other, something that is not easily fixed. But they work all right. The only thing that always bothers me is that the buttons patterns a-b-x-y doesn't follow the Snes ones nor the Xbox ones, so it's always difficult to know which one is which, something that is now even harder to figure out on the go since there is no letters anymore.
Old D-pad: 3/10 (really unplayable especially with Shmups)
New D-pad: 7/10 (might be an 8 with extra pad under membrane)
Old buttons: 5/10
New buttons: 6/10
Now one last thing. Like some people here have noticed, I too think that the feel of the new buttons are rough to the touch, don't feel smooth enough, something that has to do with the 3D printing process with painting on top. I'm now considering buying the grey ones, as it looks like they are made with a different texture (closer to plastic) than all the others. Does someone here can confirm that they are smoother?