I don't know how accurate it is, but it's hysterical...and Ironic that we can't use the title in our reviews.
But, it does have more humor than substance in it, the theories about how the word evolved and what it meant are mostly all stated and explained along with a brief etymology of the word itself and some of the myths around it...but doesn't really come to a solid conclusion.
And the inclusion and dedication to Hunter S. Thompson is well received given his love of the word and how beautifully vulgar his writings could be. It was a fitting final interview for him.
Ultimately, though, watch it for the humor. I'd take the "documentary" part with a grain of salt. In either case it will entertain.