Comment by entropicgravity

Mx Ergo (by Logitech) is far and away the best "mouse" for me and probably for you. It only takes about two hours to transfer your motor skills of regular mouse to the Mx Ergo. Because this "thumb ball" mouse only involves your thumb to work the mouse you won't get the full wrist, shoulder and neck pain that you can get from a normal mouse. If you have any kind of arm pain then check this out.