One reason I like track balls is because of ulnar nerve irritation from moving regular mice. When I move a conventional mouse on a desk, my arm rubs on the edge of the desk, over time the side of my hand gets numb. Track balls solve this by being stationary, I put mine on the edge of the desk, so my forearm doesn't touch the desk when I use it. It also doesn't need a clear spot on the desk - making more room for other stuff. It does take some getting used to - I like the kind where the thumb moves the ball, the other type has the first finger move the ball. The one I have now is a Logitech Trackman Marble - it is optical (the ball has dots on it) and corded, best of all the ball (which rides on tiny jeweled bearings) pops out easily and everything that needs cleaning is very accessable, a quick wipe with a finger usually puts it back to full functionality. They may have a wireless version - but I don't like using batteries in the office.