I'd been using the Logitech V450 Cordless Laser Mouse
over the last couple of years. I've had at least three of them. I liked the fact that they were wireless. But they've been causing pain in my wrist from too much use. They are small and portable which is great because I'm out a lot. However, it is smaller than the size of my hand so it's not as comfortable to use as a larger mouse.
Last week I got a Logitech Trackman Wheel
. While it will take some time to gain pixel precision skill in using the wheel with my thumb, there thankfully is no more pain. And as an added benefit, I can with a single sweep of my thumb get the mouse pointer fully across two monitors.