The documentary at hand is short and does feel opinionated. It starts off with high praise calling Pryor the best - and it's fellow comedians who speak out and tell their view of things. While it is short in running time, it does try to cover as much as possible, of Pryors career and rise to fame as a stand up comedian. No matter if you agree or not with him being called the best (everyone has their favorite), Pryor was one of the best.
He had to change and the documentary tells us, how that came (with a former bodyguard speaking out too). While some things may not be entirely correct (Janet Jackson and Justin Timberlake incident on live TV, no 5 seconds delay prior to that and some other stuff, that are just objective viewpoints of the interviewees), it also does not mean that the documentary shies away from darker passages of Pryors life.
What is a shame, is that we don't get some other people to talk about him. While Bill Cosby may feel wrong, after all the revelations, at least Eddie Murphy should have been in this. There's still more that could've been in this, but with direct quotes from the man (even a sort of "final word"), this does paint a picture or at least a sketch of a great comedian, who achieved quite a lot with his humor