Definitely pick up a copy of Inside the Wire: A Military Intelligence Soldier's Eyewitness Account of Life at Guantanamo by Eric Saar. If you're trying to validate a preconception (pro or anti), you'd absolutely hate it. It's very clear how grey it all is. Dude was a translator, not an interrogator, so he had only a minimal axe to grind. Mostly against bureacratic issues, not against the military in general.
He does point out some fairly "not good" interrogations and behavior by US military personnel. Some mundane, like the MP's screwing with the prisoners by stepping on their cookie or whatever. Some... not so mundane.
On the other hand, he makes it quite clear that some of these people are absolute and complete threats to the United States. Some of the prisoners he dealt with flatly told him, (paraphrased) "Dude, you're a nice guy and all that, but I'd happily cut your throat if I could."
The guy doesn't even pretend to guess at a proper answer to the situation.