After the release of All That Jazz in 1979, Stanley Kubrick reportedly believed it to be the "best film I think I have ever seen."

Given its narrative structure and theme, the central character it chose to explore, the way it used Film Language, and its overall technique and style (especially the movie's editing, for which it got an Oscar) it's easy to see why Stanley really dug this film.

Source: This was taken from the 1997 biography Kubrick by John Baxter.