Summary: It says it's 800 dpi. It's called the Microsoft optical mouse 500. The newegg item description doesn't call it that though, but that's what it is.
Pros: I prefer small mice. They're more maneuverable. This is just the right size, and very lightweight. I combine this mouse with 3M MW310LE Gel Mousepad It's like the mouse is gliding on air.
Cons: Cheap construction. After about a year, the buttons have that cheap squeaky plastic feel. So I replace the mouse about every 8 months with the same one. I keep several on hand, in the package. I go through them regularly, but keep buying the same exact one.
Pros: Easy to use on a Windows-based machine, just plug in the receiver and use it. Although I haven't measured it exactly the range is really good. Running two of these in the same room and they don't interfere with each other.
Cons: For some reason, when I plug the receiver in to the mouse port with the included adapter piece, it doesn't work. Needs a special driver perhaps?
Summary: I prefer the larger size of this mouse to my old smaller logitech mouse. It was uncomfortable and stopped working after it was a foot away from the reciever. In general I have been more satisfied with Microsoft mouses than with logitech.
Pros: I love this mouse! It is extremely comfortable and you can use it right-handed or left-handed (which can come in handy when doing two things at once) and it has an excellent price. It also has a very good range.
Cons: The one thing that aggravates me is my problem with the mouse wheel. When rolling it back it seems to stick a little and you have to hit it just right for the middle click. Other people I have talked to however said this didnt happen to them.
Summary: After going through 3 of the other MS wireless Intellimouse design mice in 3 years I thought I'd give this style a go. The other MS mouse design is one I love, but with 3 mice in a row I found the scroll wheel would get gummed up and become impossible to use after about 14 months.
Pros: Good size and weight, comfortable, long battery life