I was a 2LT on my first deployment to Afghanistan and a Captain by my third. I am guessing that the film producers used some top notch military advisors, because, frankly, the book was sloppily written and full of cliches and errors on many levels. But the film itself is, for the already problematic and almost never accurate in detail or large picture, genre of war film, quite a good film.
On of the professional reviewers I read complained about troops "bullying each other." Really? WTF. That is very accurate and perfectly natural. Everyone is on the edge of their nerves and the banter you hear is accurate. There are a few small technical problems with the way the Taliban troops are shown to deploy and fight. But overall what you are looking at in this film is fairly true.
Could it have done more to convey the visceral nature of the fighting around some of the FOB and outposts? Yes, but I am not sure how.
Give it a watch.