Definitely worth the money, imo sets the standard for any fps not just in graphics but in gameplay and freedom.
Single player campaign isn't that long, but then, what is these days. Does, however, provide great replay-ability due to the freedom in approaching objectives and the sheer novelty of it.
Power struggle in multi player i quite fun, but the absence of team death match was rather disappointing.
Overall though, one of the best fps ever, 9.5/10