They are great, but I have two issues with my left handed one:

• Right handed people just cannot use it, I can’t just give someone else my mouse for a minute.
• For some stupid reason, the left and right mouse button are switched, so now I have to switch it back in software, so now the buttons on my laptop touchpad are switched.

I tried it and I got wrist pain that I never had from the horizontal mouse

I guess my body is completely set? (been using a normal mouse for many, many hours since I was 10yo)

Thumball with 3D printed vertical stand yes I got asked about it a lot