Logitech ERGO M575 Wireless Trackball Mouse

Basically it's the upgraded model of the M570. After months of use, I can say it has pretty much the same shape. The mouse has good heft to it, so it won't move from it's position easily. Just like the previous model. Excellent. For people like me, who suffer from wrist problems, using anything but a trackball, can be trouble long term. I've been using them for years in fact. It makes working at the computer more comfortable without risking strain on the wrist. It is well worth the money. You still need to periodically pop the ball out and clean the little balls that the big ball rides on, but all track balls seem to have this common problem. Not really an issue. The battery is still going strong. You can expect 6-12 months from it, depending on how much you use the mouse. Also, it doesn't have problems with the switches under the buttons. So they fixed that problem. It's a reliable mouse. It's connectivity is excellent. You just plug in the dongle, and off you go essentially. Overall, it's a much improved product I can say after several months of use.