What a fantastic product! I started looking into the world of vertical mice after experiencing some wrist discomfort from the use of a traditional mouse. Of course, the first search hit was Evoluent Vertical Mouse. They were the first to market with a product like this, plus they have the whole University of California academic cachet behind them. For YEARS Evoluent was the ONLY player on the vertical mouse market without competition. As a result, the technology and finish of their product is still stuck in the past. Think those ugly white Microsoft optical mice we all used in the late 90s when optical mice were a novelty. The Evoluent mice have the exact same feel, and even worse tracking capability! In Evoluent's defense, their product does relieve wrist strain, but so does Anker vertical mouse...... for only $20!So let's compare the two products side by side, Evoluent vs Anker. Note that I am just over 7 inches from my wrist crease to the tip of my middle finger. This puts me right on the border for Evoluent between normal and small versions. If you are in the same boat, go the smaller size with Evoluent, provided you don't opt for the Anker.1. SizeEvoluent (standard size) felt a bit too big for my hands. The cheap plastic is also very slippery, making it difficult to pick up the mouse and move it if you are at the edge of the mouse pad (and you do need a mouse pad with Evoluent). Anker fits my hand perfectly. I simply LOVE holding the mouse. It has a really nice rubbery matte finish that prevents your hand from slipping.2. Hand PositionBoth Anker and Evoluent offer the handshake position. I would say that Evoluent hand position is about 80 degrees between table top and your wrist. For comparison, regular mouse would have your wrist at 0 degrees. Anker holds your wrist at about 65 degrees. It is debatable whether 80 or 65 degrees is better. With both mice I felt immediate relief of wrist tension. Going back to 0 degree traditional mouse position feels immediately awkward. It is a toss up between the Anker and Evoluent with a slight edge given to Evoluent, just because they have a bit of science in their product marketing.3. UsabilityThis is personal, but for me Anker wins hands down in this category. Anker feels intuitive right out the box. You click with left finger and right click with the right. The back/forward thumb buttons were also very intuitive for me. This is similar to most Logitech mice. Mouse buttons on Anker have nice rigidity to them. Evoluent, on the other hand, takes some getting used to. It is a big clunky thing that slips out of your hand. Left finger does the left click. But it is, by default, you pinkie and ring-finger that do the right clicking. You can also reassign right click to the middle mouse button, but somehow it feels awkward and you keep pressing the default right click button anyway. Also, it is EXTREMELY easy to accidentally click on Evoluent. Buttons are cheap and plastic, and the scroll wheel is a complete joke. Granted, Anker's mouse wheel is not stellar, but it works well. I must have the newer batch, as I cannot relate to any of the scroll wheel problems mentioned in review. Don't forget Evoluent's back/forward mouse buttons. They are awkward to use at first, but you get accustomed to the arrangement. Matter of preference here.4. TrackingEvoluent tracking is ABSOLUTELY TERRIBLE. I have a black Ikea Galant desk. It's not shiny, just wood with black matte veneer. Everything tracks on it....... except the Evoluent mouse. So you HAVE to get a mouse pad. And be careful, you won't get tracking on every mouse pad, even if it is matte black. This is on a $100+ mouse!!! On the other end of the spectrum, Anker tracks on everything except glass. This is a $20 mouse.In summary, there is not much to chose from in the vertical mouse arena. So get the Anker vertical mouse, get rid of wrist strain... and save Evoluent for the fanboys.