I just realised that I watched the 3+ hours TV version, which is too long, too slow and still made me feel like I got out of it with only an overview of who Elvis was by his peers, fans and family, but it somewhat lacked his point of view for most of the film, with only a few audio snippets. It seems to be an inredibly thoroughly researched film and a herculean job all in all, but still left me a bit cold.
A couple of years ago, Peter Guralnick did a wonderful 2 book biography about Elvis that probably will never be topped. This HBO doc really comes close to being it. Through visuals archives, both officials and homes movies, we get bits and pieces of his life and career. This is all done remarkably well and goes into great length into detailing his importance both as a an artistic and cultural force of nature. Bravo!