I bought this mouse about a year ago to replace my old wireless microsoft mouse. I must say that this is a great improvement. It is very light and operates smoothly. The software that came with it is easy to install and use. It allows you to change the sensetivy of the mouse on each of up to 5 levels. This comes in handy when you are playing a first person shooter and you need the decreased sensitivity for a sniper rifle. It also helps when other people use your computer and can't quite get use to the extremely high sensitivity.
My biggest problem with the mouse is the button placement. It has 7 programmable buttons, not including the click wheel. I find that the buttons on the side are difficult to reach while still retaining full control of the mouse, but that is not a huge concern when everything else about this mouse is perfect.