I have used trackballs for many, many years & have never really come to appreciate a mouse; still don't. I have used trackballs from Logitech, Microsoft, and a few others I don't remember. I really like the features of this particular trackball (Logitech Cordless Optical Trackman) except in one regard; it expires quickly.The first one I purchased lasted several months and then died. I purchased a second one thinking that the first one was an anomaly; it lasted about a year or so & then recently bit the dust as well.Strangely enough, I still have the first Logitech trackball I ever purchased; it a little grumpy but it still works. Does Logitech continue to make a product that is a loser when it comes to life span. Don't know for sure but this is my experience. Would I recommend it to a friend or enemy. NO!The sad part of this narrative is that I love everything about the trackball except its length of life and seem unable to find another with the same features.