Summary: This mouse is the best one in existence. I stand by that and have two of them that still function after all these years. I would love to curse the idiot at Microsoft who discontinued them a thousand times over. It is impossible for me to use anything else and have it work as well as this mouse does.
Summary: I have had this mouse for over somewhere around 8 years. It has been moved between 4 different computers and 5 different houses. My kids have gotten the ball out and thrown it around/played with it and it still works VERY WELL.
Summary: I bought a used mouse which has a massively sticky ball, worse than my used-every-day-and-rebuilt-twice 8 year old Logitech Trackball. If you have to do anything with precision, this is NOT the mouse to buy. Consider buying an Anker 2000 or 5000 mouse instead.
Summary: After I don't know how many years, my Microsoft Trackball has finally died. No biggie I thought, I'll just hit up Amazon and buy a new one. Maybe get a wireless model. How naive I was. I'm shocked this thing is not being made anymore. It was the best mouse replacement device I have every used.
Summary: I have used this exact mouse for about 10 years, give or take. It has never failed me and I have never had to get a replacement. All my buttons still work, lights functioning, connection is stable, etc. If you have the money, buy this mouse if you want a trackball.