I was able to procure one of those Microsoft Sidewinders pretty cheap last december, and have been using it since. It was a huge change from my old Logitech mouse in that I could use just my fingers for the Logitech, but have to use my entire hand/wrist to move the Sidewinder. All in all, I kind of miss my old Logitech more, simply because I don't need all the bells / whistles on this mouse.
And, nothing angers me more then accidentally hitting the "Macro Record" button on the Sidewinder without noticing, and then having my view freak out when the macro runs (I thought someone was hacking me the first time it happened :lol ). Having to alt-tab out and delete it, all the time fighting the mouses recorded clicks and movements is (while hilarous to watch) awful. The weights in the sucker are nice though.