So I picked one of these up to try. For some context, I've been using the Evoluent Verticalmouse and am pretty happy with it, but after a day of use I'm still getting pain on my hands and my wrist. the outermost joint of my wrist also hurts now, likely because my desk at work is a bit too high so I'm probably bending it at a weird angle. Anyway, thought I'd provide a few of my insights:
It's a fantastic piece of engineering, and i'm in love with it from a technical standpoint. However, not sure if it's for me for several reasons:
1) With the Kinesis advantage, it's a bit awkward to use because your hand jams into the Kinesis palm areas which means you have to push the kinesis farther away, which messes with the ergonomics. If the kinesis were lower and didn't have the area right below the thumb clusters (kinda like the ergodox), it would be perfect.
2) it's a bit awkward and kinda uncomfortable to pull your elbows back to use the rollermouse when switching from typing, but this may be because of how huge the kinesis is.
3) Related to the above, it increase the distance that your hands have to travel to reach the keyboard. This is pretty obvious given the design, but may mess up further with your positioning if you have a desk that is slightly too high.
4) Lastly, this may just be an issue specific to me but I realized why I stopped using trackpads so long ago: whenever I turn my palm down (like you would on a trackpad), my hand starts to get warm. I probably have messed up nerves given years of terrible habits, so YMMV on this one.
Hope this is helpful to some. I'm thinking of trying out a tented ergodox to see if it helps with the positioning. I really want to love this thing!! I'm a sucker for slick engineering. I do wish the buttons were a bit softer to click though. They have a bit of 1990s hard-clicking-mouse feel to them.