What I played of it wasn't buggy, but it was AWFUL. I can't remember if I played it on the Playstation or Xbox...I think Playstation. Looks nice, ran well...but just horrible, painful gameplay I wish I could pull out of my brain.
I can understand how some people could love it though, but I think it's a really love it or hate it game, and it's not a normal FPS (or something like Bioshock/Deus Ex for that matter either).
For myself, I hate every design decision they made.