The movie's fairly impressive photography is probably its strongest point, along with the novelty of its being a movie about the FARC. As far as those aspects go, the film would deserve a 9 or a 10.
Other than that, the rating quickly drops when the content itself is analyzed. For those that actually know more about Colombia than the average European left-winger (or right-winger, for that matter), it is sorely lacking. The film doesn't ask any tough questions, it simply passively accepts and reproduces exactly what the protagonist and the guerrillas want their audience (ie: non-Colombian foreigners) to see and hear, and nothing more.
The film feels flat and lacking in context. For the most part, it just shows a girl joining the FARC, receiving training, interacting with other FARC members, having a conversation or two with her family by phone, and finally becoming "combat ready". That's it. There is no tension, no serious debate about the issues, no sense of moral ambiguity, no real action, nothing else. It's all too simple. The message that the movie wants to transmit, and which according to interviews on the web was already clear to the authors long before the film was made, is that "FARC guerrillas are also human beings".
Of course, nobody doubts that the FARC is made up of human beings. Hey, even the paramilitaries are also human beings, just as Al Qaeda and the CIA are human too. That, however, does not excuse the actions of any of them.
A documentary that aims no higher than that is not one that can survive repeated viewings. Even the imperfect "La Sierra", another documentary on Colombia and which deals with urban gangs linked to the paramilitaries, is a much better example of how to address some of the complexity of Colombia's current conflict, without falling into intellectual and moral passivity. Sadly, "Guerrilla Girl" pales in comparison.