Pros: I have been using trackballs for many years to prevent straining my wrist, because a regular mouse creates soreness within minutes of use. This trackball is a very similar design to the wired Logitech I have been using the last several years, so it has an excellent ergonomic design. While I was concerned about a wireless mouse functioning through my KVM switch, I found no problems. Using the same monitor, keyboard, and trackball, I can switch between using my two computers with the KVM switch, without a hitch. (In case you did not know, a KVM switch allows you to hook up two or more computers using only one monitor, keyboard and mouse.)
This mouse set up automatically on both computers. The Logitech software allows you to program the buttons as you please. I like to use the scroll button to minimize a screen, and scrolling to be six lines at a time. The back and forward buttons can be programmed to do different tasks, but I find them useful as they are. The battery life appears to be very long – after about 30 hours of use, the Logitech software indicated I had over 540 days of use left!
Con?: The only con for me may be a pro for you-the four pads on the bottom of this mouse keep it secure in its position on a table, so you have to tilt it a little to change positions. As I frequently change positions in my chair, I put pieces of cellophane tape on each pad, to make it very easy to move on a table.