I preface this review to inform you that I am no mouse expert, but for those of you looking to find a cheap, great, reliable mouse, then the intellimouse is probably the mouse for you. I've had this product for about three years and it still functions great and I still love it. The plug and play USB works with every computer I used it with. I don't know much about optical DPI but its accurate enough for my workspace and its accurate enough for my gaming. The middle mouse scroll is not loud at all and rolls smoothly.
My favorite feature is the two buttons that are off to the side. I primarily use these for internet browsing as they function as the back and forward feature. Although it does not seem like much, I now never have to navigate my mouse to the top left of my browser to go back. Most of the time the buttons are unobtrusive but if you are not careful, you may press the back button when writing an e-mail and lose all the text you've written, but this is the risk you gain when using such a feature.
The optical intellimouse is an awesome basic mouse that fulfills easy internet browsing as well as great gaming.