Summary: i picked this item up, still needing two more surgeries in my wrists, and boy oh howdy am i glad i did. it took a little time to adjust to its unique style/design, but i am glad i took the option because i am loving it. it could a little less expensive but it will do fine for my needs.
Excerpt: I have had problems with my hands stiffening up and a little arthritis too. This mouse helped SO Much! Takes time to get use to it but afterwards what a pleasure to use. Don't want any other kind.
Summary: Unless your palm is significantly wider than 3.5" I recommend the Small size. The 550 has a better surface and optical sensor than the 500, but the batteries need to replaced from time to time.
Pros: Much more comfortable than standard mouse designs. Virtually eliminates hand strain. Rubberized surface feels good and does not collect too much dirt. Includes 3 mouse buttons. Wireless removes annoying cables.
Cons: My hand is 3.5" across the palm and the Large size is way too big for me. The wireless signal is not that strong, so it helps to be near the receiver. The batteries add weight.
Excerpt: This mouse lets you keep your hand in an anatomically neutral position while using the mouse. I bought this when I was diagnosed with tendonitis in my elbow. Using a regular mouse was painful after about an hour. As soon as I plugged this mouse in, the pain was gone and did not return.
Pros: After having carpal tunnel surgery I started using this mouse and I would not go back to the old style. I work on the computer all day and my wrist does not hurt like it did with the other mouse. I highly reccomend this mouse if you are showing signs of carpal tunnel.
Cons: It takes some getting used to as you are moving your amr and not just flexing your wrist. After a little use it becomes natural to use.
Summary: I have been battling carpal tunnel for years now. Forget any of the bad reviews from previous customers. If I could give a 6 stars to this, I would! Yes it takes a little getting used to, but who freakin cares if it solves the physical pain.
Summary: I bought this mouse about 3 years ago. I liked it so much that I bought another one for work. The construction quality is great, it feels solid. It's reliable and precise and of course, very comfortable. I use it 10 hours daily, 5 days a week.