This vertical mouse is more vertical than most other products out there, such as the Logitech Vertical MX.
I like a larger size than my hand measurements would indicate, because I like to relax my hand and have it well supported. It does take a few days to get used to using it, but it's worth it.
The multiple buttons are great. I've got one to close a window (which in Chrome has an app-specific setting to close a tab instead). You can set up the number 6 button (at the bottom of the thumb) to be like a shift key for the other buttons, supporting a second set of functions.
(Amazon just called me a potty mouth. Sorry.)
I know the mouse seems a bit to shiny and slippery at first blush, but it actually isn't a problem for me, keeping it in my hand. I'm happy this version doesn't have the spray on rubberized finish, because a search of eBay for used ones shows that that finish will deteriorate and peel off, and because I have touch allergies to similar kinds of rubber coatings.
I like the little dips for the fingertips on this model very much. Helps to feel oriented on the mouse, especially for beginners. I have occasional trouble with tracking, but it doesn't last, and I suspect that's only when my computer is a bit overloaded doing other tasks.