Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Be warned - no middle mouse button

I like Logitech mice in general and as this one is the new "top of the line" I gave it a go. It's well built & designed, and feels pretty comfortable, but there is one major drawback which caused me to return it. The new fancy scrollwheel cannot be used as a regular button - wheel click is hardwired to change the scroll mode. If, like many people, you're a user of software which makes use of the middle button (like Firefox) then forget it. I can't believe Logitech made such a nice mouse and messed up on such a basic feature.