It's a fantastic piece of filmmaking -- an audacious, genre-defining, financial, technical, logistical and artistic achievement, suffused with magic, humanity and wonder. A true marvel in the field of fantasy cinema!
The bucolic feel of the "Smallville" act, epic yet intimate, slow yet enervating, grand yet subtle, is still one of the greatest passages ever found in a motion picture. The dialogue, photography, music and performances cohere perfectly. It rivals a David Lean picture. And it's SUPERMAN! Lean may have mythologised the desert and the steamy jungles of Ceylon, but could he have done what Donner did and mythologised Superman?
I don't think many people quite realise what the filmmakers -- that's Donner, the Salkinds, Reeve and everyone else combined -- were truly up against, least of all the filmmakers themselves at the time! The film was a gargantuan effort and required nothing less than an Olympian show of strength and endurance to pull off. Read the "Making Of" by David Michael Petrou for more. They were facing near-impossible odds. It burns my heart that the Academy didn't decorate it but finally recognised a comparitive walk-in-the-park and relatively staid film like "Lord of the Rings: The Return of the King" in the "Best Picture" fantasy field. People often rave about "Star Wars" and "The Empire Strikes Back", but they forget about "Superman" -- a picture that is at least their equal and possibly their superior.
I will admit that my loyalties are somewhat torn between "Superman" and "Teenage Mutant Ninja Turtles" (the 1990 movie), since I rate both very highly. If "Superman" hadn't have come along, "Teenage Mutant Ninja Turtles" would be the best, IMO -- but "Superman" did come along and that's really that. However, "Teenage Mutant Ninja Turtles" might still have it because the ending is tighter and more sensible, whereas the ending to "Superman" strains the verisimilitude that Donner strived in earnest for. Superman should have paid some price for what he did. On the other hand, his actions are memorable and give the film an even greater poetry. It's a very tough call. Ultimately, "Superman" is the more important of the two. It's a movie that needs to be respected like fire.