The film is mostly a series of interviews with former soldiers in Iraq, all of whom became opposed to the war at some point (many of them after witnessing or participating in the killing of civilians). The film has them recount their experience, from entering the army to being deployed in Iraq, to returning home (several of them injured for life and suffering from really acute PTSD). While the film has a clear agenda, it isn't strident, and the interviews--the personalities and stories of the soldiers--are so interesting that they carry the whole thing easily. One thing that becomes very clear is that from basic training on (where the soldiers chant songs about "Hajjes" and shoot at "Bin Ladens") a willful conflation is created between terrorists and Iraqis, or Afghanis, or whoever the army will fight--and that that conflation only gets worse in Iraq and leads almost inevitably to the indiscriminate killing of civilians.
The three veterans, who spoke after the film, were also very compelling. They were all pretty young, two men and a woman, and as far as I remember, two were from the National Guard and one from the Navy.
Several of them talked about how the army had been an economic opportunity for them and also about how the culture of the army had made it very difficult for them to be critical of the war, to speak out, and to ask for conscientious objector status--they said it was seen as a betrayal and a criticism of friends and colleagues.
They also spent some time talking about veteran's benefits. As Matthew pointed out recently, the number of wounded US soldiers spiked recently. One thing to keep in mind is that "wounded" in Iraq often means losing one or more limbs (basically, losing the part of the body that aren't protected by body armour). These soldiers come back and face months of red tape to get medical benefits. Also, apparently there is a push to categorize people with PTSD (and one imagines there are many, given the length and strain of current tours of duty) as having "personality disorders" or being "bipolar," so they won't get benefits. The government has also cut funding and discouraged doctors from diagnosing TBI (Traumatic Brain Injury)--something that can happen when you are exposed to a lot of explosions.
At one point, a man stood up in the (smallish) audience and said he was a member of the Navy who had served in Iraq and he thought the film was biased. He talked at some length and seemed to me, to be honest, a little strange (although maybe he was just worked up). He said "9/11 was only five years ago, have you forgotten already?" and complained that the film showed the US military in a bad light but didn't show all the terrible things that "they" (the terrorists) did. He said "Have I seen a lot of action? Definitely. I got more medals than Patton. But I don't like to talk about it." He also said, "It was some hardcore shit. We defended American freedom. We were men. We used to hunt those guys down."
What really impressed me was the reaction of the Veterans Against the War. While the room of NYU students sat in shocked silence and indignation, the veterans responded perfectly: they thanked the man for speaking, thanked him for his service, reiterated the fact that 9/11 was not in fact carried out by Iraqis, reiterated the fact that the insurgency in Iraq is a reaction to US presence there and asked him to come out for a beer after and talk about it all some more. It was a humbling lesson in how to be an effective advocate. If you want to change people's minds, you have to know how to talk to people you completely disagree with.