Instruct: Classify an Amazon review as either positive or negative.
Query: Great ergonomics; Poor function

Although this mouse feels great in your hand, it has the worst tracking I have ever seen. So bad it's frustrating even while surfing the web, much less doing something that requires precision.Logitechs "Cordless MouseMan Optical" proves that it can be done right (very precise tracking.) So until Microsoft gets it right, my advice is to go with Logitech.