It's nice to hear so many fantastic filmmakers talking about their craft, but this also limits how deep the film can go. It would have been much improved by reducing the number of filmmakers to 3-4, adding a critic or two (talking about film is not the filmmaker's area of expertise), and focusing in on the central questions: "How do documentary films work, and to what ends?" As it is, it doesn't do much more than acknowledge the uncertainty.

Add 10 if you actually want to become a documentary filmmaker.

It's nice to see what documentarians say about the medium. There are a lot of different opinions, sometimes in direct contrast with each other. The film tackles issues of documentaries like sound, re-enactments, facts, the dangers of documentaries, etc. It's never boring, usually insightful and it plays to its theme well: That there are so many ways to do it, and so many ways to view the medium, like there is truth and the pursuit of it. Plus it has Werner Herzog.