I have a very modest PC, but here's my experince.
I play high settings, 1080p, no AA. I get a solid 30 - 50fps.
Rig Specs:
AMD Athlon II X4 @ 3Ghz
3GB DDRII 800 RAM
Radeon HD 5770
I'd say I'm quite happy with the performance, it's not a blistering 60fps but the game is smooth and looks great.
