This is my favorite laptop mouse of all times! I have tried several other mice in the past, including Microsoft Explorer Mini Mouse, which is great too, but I've never liked the 'smooth' mouse wheel. This Logitech mouse allows you to choose between both, which is a plus! Battery life is great too; it's been over a year now and I'm still using the same batteries. The quality/feel of the mouse is very durable and feels great in my hands. Although smaller than I would like, this is a 'laptop' mouse and I have no complaints on that.Usability, I'm writing this review using my mouse on my bed as the surface and it works great!The usb transmitter is small enough to leave it plugged into my laptop at all times. On the mouse, a coool feature of turning it off and protecting the lens from dust is very convenient too!This mouse is quite expensive, I agree to that, but if you can, wait for rebates. They have it every now and then, even after a year I still see rebates out @ Amazon.Also, one more thing about this mouse is that I live in a pretty high humidity location (Hawaii) and it affects some of my desktop Logitech mice's texture. (eg. MX1000) For some reason on the sides, the thin layer material tends to swell up and deteoriate over time. This mouse doesn't have that problem.Not much else to say that other reviewers haven't said, but I'm getting one more as a gift! Highly recommended! 

Question: How is the button?
Answer: This is my favorite laptop mouse of all times