I just noticed it in the pinned "Ergo Product announcements" thread. It's certainly a very interesting design but I have some doubts.
I can't imagine myself moving a mouse of *that* size. For the mouse to work, it needs to glide smoothly, which means it may just move when you are typing. The trackball version seems better for stability.
The F-keys are tiny. Probably better just to have them programmed into a layer of normal-sized keys.
Does the big hump in the middle get in the way when you're reaching to the keys at the outer edges? Given that the thumb keys are quite low, do you have to roll your wrists frequently?
Show Image
(https://www.keymouse.com/media/com_eshop/products/resized/KeyMouse_Track%20-%2003b%20600x600-600x600.png)
The frick is that big hump