I get terrible pain if I use the Magic Mouse for more than an house, which disappared after I switched to another mouse. One thing I dislike about the Magic Mouse is that if I rest my finger on the 'button' area it registers it as a click so I always have to hover my fingers above the 'button' area—something I suspect contributed to my pain. With normal mouses I can rest entire my hand and fingers over the mouse and the only force I have to do is when I press the buttons.