Sounds like you made a decision, but if you haven't, one more vote for the mx revolution. I've had it since spring, and it's great. I am a little unimpressed with the SetPoint software Logitech sends with it. Sometimes it will reset your settings, not completely, but just certain buttons. Like I have the tilt on the scroll wheel as my volume adjustment for everything by my web browsers, but sometimes it resets it to side scrolling to everything. But it works great with OSX. I set the thumb wheel to the application switcher, and the thumb wheel button show all windows. I set the scroll wheel button to dashboard, and the next and last keys to next and last track in itunes(by downloading GimmeSomeTune it makes command+option+right go to next track no matter what program you are running(except fullscreen games, etc.)) and the search button i have set to spotlight, but you can set it to open your web browser and go to google. or do anything else you want. I tried to assign it to command+option+D, so I could hit it to look up any word in dictionary, but for some reason it won't work.
Anyway, the mouse is great, I recharge it about once a week, which is much better than switching batteries once a week. I don't know what they are running now, I got mine for $100, and I think it was worth it.
The Mighty Mouse scroll wheel is unbeatable, except for that it hangs up easy with dust.