I've used some "vertical" mice, and found them a hella lot more comfortable. It doesn't keep your hand fully 90º compared to the surface, but it's enough to feel the difference. My ex didn't like it, so it's a case of ymmv
I have the opposite experience. I noticed that my arms had a tendency to “roll outwards” when using normal mice, so I switched to a vertical one. Most uncomfortable mouse I’ve ever had. Switched back after 2 weeks.
Last I heard the mouse's were tilted less than 90 cause natural and relaxed was a bit less than vertical
•
Have the best of both worlds: an optical tracker affixed to the bottom of the rodent mouse/rat. Then gently steer the rodent in the direction of travel, giving it cheese when it complies.
"When the patient woke up, his skeleton is missing, and the Doctor was never heard from again! Anyway, that's how I lost my medical license"