It's a really strong film, with some incredible set pieces. Cinematography is some of the best I've seen all year- the s16mm coupled with zoom lenses perfectly suits the mood of the film, and as an added bonus, looks beautiful.
It's not a overly thoughtful comment on war, nor a complete reflection of the madness of the whole thing, but a wonderfully subtle action film, with a very strong performance from Jeremy Renner.
I've always liked Kathryn Bigelow's early feature Point Break, but I've only just realised why- the action is superb. Her set pieces are rivaled only by the best scenes from the Bourne films. Witness the agonizingly long sniper scene in Hurt Locker. Like Greengrass, she brings a sense of realism to the action that utterly draws you in.
Go see it. It's the most thrilling film of the year to date.