Summary: I used one of these I bought years ago until it died (I dropped it too many times!), so this is my second unit. I love the fact that it minimizes wrist & finger fatigue. What I don't like is it takes a bit of concentration to make sure your left click is an actual left click, an issue I don't recall having with my first one. Also, the front button which replaces the scroll wheel doesn't seem to work on this one, either.
Summary: I purchased this product on the recommendation of my physical therapist, since traditional mousing was aggravating my "tennis elbow" significantly. It provided immediate relief while mousing. I have used it for about 3 weeks with no problem, other than the learning curve associated with buttons being located in different places than I was used to. I have not experienced the problems that I've read in some reviews (so far).
Summary: I just bought my 3rd one of these, and that says it all. The 1st two broke; the part where the vertical handle joins the base is narrow, which makes it too weak so it snapped there twice. However, it was so good for my wrist that I figure it's worth the price to buy a new one every year. I tried another widely-sold ergonomic mouse, but it wasn't as good for my wrist, and anyway it broke too. Maybe I'm just hard on mice.
Taking a bit to get used to and wrist angle feels a bit strange
15 March 2013
Summary: Just received the new mouse. Install went smooth but it did take a full 5 minutes for the drivers to install. Getting used to the right and left mouse button is easy. The scroll function buttons are on the stalk and requires a button push and then a repositioning of the mouse to scroll up or down. I wear a large glove size and noticed my hand feels cramped on the stalk so be aware if you have very large hands this might not be for you.
Summary: I bought this to address carpel tunnel pain. It worked like a charm! My hand/wrist feels fantastic with this mouse. The USB adapter is a little big and may need to be placed at the top of a vertical stack of ports. The scroll function works 75% of the time. The other 25% you need to pull on scroll bars. Overall, if your wrist hurts, buy it. I'll gladly deal with the issues above than the CT discomfort.
Summary: This was bought for someone for someone who has carple tunnel syndrome. This mouse provided a relaxed, but supportive wrist position which has helped to relieve pain and provide comfort. It is easy to install and easy to use. She had previously used the product, but not without the wireless capacity which has made it easier and more efficient to use. She would recommend it to anyone who is on the computer for extended periods of time.