I have this mouse and it is the absoltue best mouse I have ever owned or tried. Very smooth, use on a pad, off a pad, use it from 20 ft away on a hardwood floor (I have tried it!!)
It has a rechargeable battery that lasts forever, is EXTREMELY comfortable in your hand and has a multitude of controls at your fingertips. (scroll wheel up and down as well as left and right, a button that works like the command+tab button feature, etc. All are programable via a system preference. Best of all, it was recognized as soon as I plugged it in.
Can't say enough about it, well worth the $79.