You DID know that turning V-Sync off makes it pretty ok, right?
(The game was still a borefest, though...)
Turning off V-Sync did indeed solve the problem with the mouse, but at least on my system it turned on the horrible, horrible screen tearing.
If you have an Nvidia card, you can force V-sync from it's Control Panel and everything is fine again. 60 FPS, while the game v-sync setting locks it at 30.