I always find it interesting how people disagree on films in this genre. For instance, I think FOR A FEW DOLLARS MORE is Leone's weakest western in that it drags so badly in the middle. Other fans call it a masterpiece. It all boils down to personal taste.
As far as Gemma's films go, personally I like RETURN OF RINGO better than PISTOL, but like DAY OF ANGER equally as well. I went club-hopping with Gemma in the late '60s in Hong Kong and he seemed content to do most any film, as long as he got the star treatment. I consider PRICE OF POWER in a class by itself, because it transcends the action genre and, unlike most spaghetti westerns, has many unexpected plot twists in a very serious, well constructed, and intelligent script.