Canon L or Sigma Art?

Hello! I am currently in the market for a new lens and wanted to come here to gather some input.

I currently own a Sigma 35 and Canon 70-200.

I was wondering if anybody here had any experience with the Sigma 24mm Art, Sigma 20mm Art or Canon 24mm II. Those are the one's I've been looking at and every review is different. Some say Sigma is better and some say Canon is better. If anybody could give some input, it would be greatly obliged!