I've had both the wired and bluetooth versions. In short, I wouldn't recommend it. I found it sits too low to the desk to be comfortable (although I have slightly big hands) and the wired version is too light.
My biggest gripe however was that you cannot right-click whilst your finger is resting on the left hand side - you have to totally lift your finger off the left surface for the right surface to register a click.
I've since bought a Logitech MX Revolution. Expensive, but amazing. It's got 13 buttons. 13! I can open, navigate and close multiple tabs in Safari without moving the mouse once. And it's ergonomically designed, so it takes twice as long for your wrist to hurt. The ratchet/freewheel is amazing, I can select and scroll through documents like lightning. Anyway. I like this mouse.
Failing that, go for a Logitech MX 700 if they're still around. A cheap but equally amazing mouse.
AppleMatt