It is good. It has an 80% on RT's and that is an appropriate score, 4/5 on our rating scale. I don't usually like watching these types of movies, but at the end, I was glad I had.
75% documentary and 25% dramatization. So, there is some fictionalization. Like, Wahlberg's character is the combination of two real life individuals that played the major roles he did in the movie. Yeah, there are more explosions and dramatics during the gunfights than probably actually happened... but who cares. It makes for a more intense and exciting movie. What is important is that he still stays true to the people that lived through these events, telling their tale.
Peter Berg always makes sure his characters have heart and feel like real people. He tells stories of normal people that matter and have done some heroic things. If you are too cynical to respect that, you may need more life experience under your belt.