It was an awesome input device, until a couple of months after I bought it the mouse started acting squirrely. The cursor would stop reacting to the mouse every few seconds, and clicks would either not register or would register as double clicks. The receiver was only 2-3 feet away from the mouse, with no major obstructions besides the computer desk. I changed the batteries so many times. I even bought those fancy Radio Shack batteries advertised as special for computer peripherals. Needless to say fresh batteries were no help.
Unrelated to the review of best computer mice, but relevant to Logitech's wireless peripherals, I had a miniature wireless laser mouse for laptops that did the same thing.