This is definitely the best one. I admired the charm of how cheap the previous films looked, so it was actually a pleasant surprise to see them transition into a real Hollywood movie. Tons of great shots. Leone clearly puts all of his passion into these things, and also takes criticism to heart. People complained about the first having no story? Well now theres a franchise spanning story about the battle between good and evil. Part 2 was too long? How about we smash cut right into the finale when nobody is expecting it. All of these things improve the experience and make the movie feel so very cinematic even when legitimately disturbing things are happing. Murdering children by hiding a bomb in a christmas present? Check. A woman masturbating with a shard of glass? Check. Art ripping the face off someone's skull? Check. This franchise is still clearly only for sickos, but I swear its way more interesting than many of the slashers it took inspiration from.
I'm going 9/10. I'll probably adjust it down after the hype wears off, but maybe it'll become one of those classics that gets revisited every Halloween (and maybe Christmas)?