I picked up the original Dead Space on Steam this weekend for like 7 bucks. It's kind of funny because it's so painfully obvious the game was designed for consoles.
There's so many parts where something jumps out of the floor, wall, off the ground, etc etc and starts coming towards you. Sometimes there's more than one, sometimes they run and jump a little. They give such a huge amount of time to react to everything, you might as well be shooting ducks. I suppose carefully aiming and shooting off limbs of several necromorphs in a group would be tough with an analog stick, but with a mouse it's a fucking joke.
Anyhow, you have a powerful gaming rig, so you should use it. Go with the PC version.