I liked the Donner Cut a lot though it was far from perfect. Having Superman turn back time at the end, thus negating everything that happened is unforgiveable. The diner revenge afterwards makes no sense because of the change. There's also the little things. Superman's "General, would you care to step outside?" in the Lester version is a THOUSAND times better than the "General, don't you believe in the freedom of the press?" line from the Donner Cut. Replacing a superior line from the Lester Cut with an inferior line from his own cut was a petty move by Donner. Just acknowledge that the line Lester Cut line was superior and keep it in there.
Anyway, where the movie thrives is the inclusion of Jor-El and more from Christopher Reeves. I think some of Reeves best acting in these films comes from the Donner Cut. The way he transforms from Clark to Superman with just a look after Lois fires the blank is brilliant. There's a scene later in the Fortress where he looks like Superman but is dressed like a civilian. He just knew how to make that look work if that makes sense. Adding Brando back into the mix enhances the story greatly.
It might be a rough screen test but Lois managing to get Clark to "out" himself was also better than the stupid "trip over a rug and into the fire" scene from the original.