For over 10 years I have used the Microsoft 4500 mouse and been very happy with it and still as good when I bought it. Just recently bought 2 more. Unfortunately not the same spec. The mouse works excellent in the ways the old one does but when using the wheel to move up and down the web page you have to sure you have your finger over the front of the wheel. If you have it further back after a while your finger feels sore as it catches the edge of the casing, This is due to not being built to the original spec. 1. The mouse is narrower. 2. The wheel is smaller so is not as high as previous model so you catch your finger. I still find it excellent but having to learn to do above.