Not a stellar port, IIRC there's no gamepad support and if you want to invert the Y-axis on the mouse you can't do it without inverting X as well. Madness.
I also had some graphical issues that can only be fixed by disabling the "HW Vertex Processing" option, which would result in really poor performance. See this thread:
http://forums.steampowered.com/forums/showthread.php?t=682893 . Might not be an issue on a semi-modern machine. Also think cutscene audio could go out of sync on 2+ core machines, maybe manually assigning the process to a core in the task manager is enough to fix that.
I loved the game on the Xbox, but I regret paying ~2 for the PC version.