I haven't played the PS2 version but I do have it on Xbox and I think it's really good. It's incredibly atmospheric and not really like any other military FPS game out there. I'd avoid it if you are expecting all out action as most of the game is spent planning, seeking cover and camping. The sim aspect, difficulty & surprisingly good AI make every kill much more satisfying though.
I haven't played it online yet but the Co-op campaign was fun when I tried it with a mate.