There's a wonderful backstory about the making of Act of Valor which explains why it is such a great action film. Basically the directors were hired by the US Navy SEALS to shoot a series of short training videos. Somewhere along the line, one of these training films for the US Navy's elite special ops force grew to become a feature film with all of the action scenes, almost all of the actors playing the SEALS, and much of the script in the film done with the input of the US Navy.
The result is a action war film that is designed to be as realistic as possible. As a bare minimum, military fans will have fun identifying the types of weapons and military hardware showcased in the film. Yet because of its beginnings as a training film for the SEALS, the missions are also a showcase for rarely-seen special ops tactics and planning, which impose a deliberateness and methodical caution to the armed engagement that we would not find in other army-funded action blockbusters.
And unlike other action blockbusters with a military theme, Act of Valor is filmed very conservatively, without the jump cuts, fast edits, nausea-inducing handycam, and rock soundtrack gimmicks that have defined this genre the past few years. Bucking this trend, Act of Valor proves that people will want to watch a well-written action film, and want to watch it without having to figure out what exactly happened in the messiness of the action.