I saw Silver Streak as a kid and laughed my ass off. I have also enjoyed Pryor's stand-up comedy. I think it's interesting that most reviews in here are either 5-star, or 1-star (with most of those taking offense to the "foul language.")
From all of the famous comedians who honor him, I understand that his contribution to comedy has been great. However, Lenny Bruce also was a great influence in comedy (especially darker, social commentary). He came before Pryor and unfortunately was not allowed to pursue his career by the government's emphatic persecution under its censorship laws.
Pryor is definitely an original, and he completely stood out among the rest during his time. However, now there are other comedians that make me laugh harder.