I saw him in concert a couple of times. A great performer, and a great musician. I hate the word "pioneer" when applied to entertainers, but he truly was. He took some riffs from blues players such as T Bone Walker and mixed them with his own to come up with a radical new sound. The Rolling Stones would never have become a supergroup without Chuck Berry.
He was also incredibly athletic. His duck walk, splits, and other moves while playing take enormous strength and skill.
He was bitter most of his adult life over being screwed by the music industry, and rightfully so. He, Little Richard, Bo Diddley and other black performers got screwed on their records. The Stones made hundreds of millions of dollars from playing his music, while he made maybe a few million.
He was a difficult person to work with, and could be an a*****e just for the sake of being one, but the results were always great.