It rocks, it is wroth every single penny of the $80.00 I spent on it. I wondered how its response would be and it is perfect, I have not experienced a snag or stutter once since owning it over the last two weeks. It is VERY ergonomic in its design and the buttons function really well on it. I especially like the application switcher. Also, it seems to work on any surface.. flawlessly. No more mouse pads for me!
If you are in the market for a great mouse then this is it, also it has a sleep mode so not to drain the internal batteries, and a cradle to recharge it.
You can check it out here