I use an Ergodox. I have long thumbs but can only comfortably reach 2 (3?) of the 6 buttons in the thumb cluster. The whole point of the Ergodox for me was to avoid uncomfortable movements, so I don't use those keys.

I'm happy with the Ergodox, but if I ever need to replace it, I'll be looking at something with a reduced key set such as the Gergo.