Sacotool,
My girlfriend and roommate both own that mouse. I have never experienced what Viper is talking about as far as slowing down, and to me using USB offers smoother, faster response while gaming, which is important to me if I'm playing Quake 3. The safe mode support could be an issue, but any USB mouse you buy, will almost always come with a ps/2 adapter. The logitech is that way as well.
dm