I actually used a Razer Imperator, but I found it to be very flaky: about once an hour it would lose the plot completely and I'd have to unplug and reinsert the USB cable. Not a great experience in-game :-( I don't know if it was that particular mouse or the OS/X driver that was causing me problems, though.

I switched to a Steelseries Xai, and I've been loving it. It doesn't have any special mac drivers but all of the fancy settings are controllable via a little LCD screen on the bottom of the mouse.

I'm not sure if its affected by this "32 ms" problem. I only use OS/X so I might just be used to it at this point.