I dunno. SUPERMAN III is kind of fun.
It's the closest we've gotten to a straight-up movie version of a Silver Age Superman story.
SUPERMAN IV is an attempt at a 1970s "relevance" story but unfortunately written and drawn by Rob Liefeld instead of Denny O'Neil and Neal Adams.
SUPERMAN: THE MOVIE and SUPERMAN II are sort of your "greatest hits" collection of Superman stories: There's Krypton! The Phantom Zone! The Fortress! Daily Planet! Superman saving Lois. Superman facing off against Luthor, etc.
But SUPERMAN III feels the most like a two-part Silver Age story. And yes, those stories could be crazy -- like when Superman fakes Clark Kent's death to psychologically torture Lois Lane (no, really). 
It's strange to me that Richard Pryor's Gus Gorman character is severely criticized as if that's the first time humor encroached into the series. Gus is basically Otis but with an actual plot function and relatable motivations.
Also, unlike Miss Tessmacher's "heel face turn" in SUPERMAN, which is entirely self-motivated (saving her mother's life), Gus switches sides bc he genuinely doesn't want to see Superman die. He's confronted with the brutality of his selfish actions and changes.
I'm sure SUPERMAN III is probably a film my kid would be able to sit through and enjoy at around 8, as opposed to him falling asleep before Superman shows up in the first Donner film.
