The support for this mouse for both my OSes (osx, vista) is pretty broken out of the box, but once you get online and update, the software is pretty amazing (well, it was to me, I dont' really have a lot of experience with mice!)
anyways, I got this mouse because it was bluetooth, and since I use an MBP, I'm kinda hurting for usb ports and have bluetooth I'm typically not using.
Well, it turns out that they have this ridiculous usb bluetooth dongle which MS claim is the only way you can use their mouse. Okay, whatever. Luckily there are some wonderful people who can help you remove your dependancy on this completely useless dongle.
However, compared to my other "mouse" (a mouse-shaped stylus that goes to my wacom intuos 3 :p) this thing, minus all the bluetooth details, is a dream. It comes with a rechargable double A (although the retailer I got mine from didn't include the power adapter, D'OH, but shipped one as soon as we told them), plenty of buttons (although the scroll wheel doesn't so much scroll as glide. Think one that you've had for so long it doesn't click anymore ;.; )
Anyways, I pretty much fell in love with it, and it allowed me to finish my CAD assignments without spending every moment at the computer labs (have you tried working in autoCAD with a touchpad? It's impossible. my god.)
so, just my experience ^^^