First, a disclaimer. Despite a fair amount of research and even the backing of the Evoluent design by the University of California at Berkeley, no agreed-upon ergonomic standard for computer mice exists. Thus, neither CNET nor anyone else can really point to any mouse design as superior to any other. If you are experiencing repetitive-stress-related discomfort due to using your computer, you should definitely seek out the advice of a doctor.
The new VerticalMouse 3 looks very similar to the VerticalMouse 2. As for the "Rev. 2" in the product name, Evoluent informed us that it indicates the model with a DPI switching button on the bottom. We'll go over that feature in a minute, but needless to say, we'd rather have the button than not.
From the VerticalMouse 2 design, Evoluent says it reshaped the grip for a more universal fit on the VerticalMouse 3. Astute observers will also notice a lip on the bottom-right edge of the new mouse, which Evoluent added to keep your little finger up off the desk surface. Cosmetically, Evoluent also made the buttons silver, updating the purple from the previous design.
Compared to the Microsoft mouse, the Evoluent design cants your hand up at a more severe angle, positioning your hand nearly perpendicular to your mousing surface. The idea is that gripping a traditional mouse makes you twist your forearm in an unnatural manner. Ideally, ergonomic experts say, you would grab the mouse so that your palm is about 90 degrees to the table top. If indeed it's true that the closer to perpendicular the better, the VerticalMouse 3 does a better job than Microsoft's mouse at keeping your hand and forearm in the proper position.