But if you can look past inherent flaws that comes with the circumstance obvious dubbing issues, inconsistent special effects, glaring continuity errors, a recycled resolution, and lack of an original score look past all of that, look to the underlying vision, and you'll see something special.
First and foremost, the return of Marlon Brando's scenes, a presence sorely missed in the theatrical cut of Superman II which allows the characters and story arcs that started in the first film to come full circle. At last nonsensical dialogue from the first film clicks into place "the father becomes the son, the son becomes the father" it gains a meaning in a touching exchange between Jor-El and Kal-El. In the Lester cut, Kal-El consults his mother in the fortress of solitude, and somehow it lacks the emotional punch that the exchange should have. Here, though, in the Donner Cut, Marlon Brando's voice rings with fatherly love, and across time and space the essence of the father reaches out to the son. A love that allows Jor-El to guide Kal-El even from his Kryptonian grave. And after 25 years it finally makes sense how Superman regains his powers after sacrificing them to live with Lois Lane.
Marlon Brando as Jor-El by itself makes the Donner Cut worth the price of the rental. I mean, how do you cut out Marlon Brando? Especially when his character is integral to not only the plot, but to the titular character's arc? Anyway, I particularly liked the restoration of how Lois initially suspects Clark's identity. A passive comment by Jimmy Olson makes her pause and ponder the paradox of Clark disappearing when Superman appears, and she draws a suit, hat, and glasses over a newsprint picture of the Man of Steel. In the Lester version, Lois' eventual revelation feels more chance driven, and even when they have direction it's as though they beat around the bush. It's anti-climactic, and lacks a fulfilling payoff.
In Donner's version, by contrast, the challenge is more direct. A one on one battle of wits with Lois fighting to conclusively prove that Clark is Superman, while he makes clever use of his powers to keep his identity hidden early on Lois throws herself out a window. And instead of Superman flying to the rescue, Clark uses his super-breath to slow her descent, and his eye beam to unlatch a canopy to break her fall. She lands safely, and lo and behold Clark hasn't moved from the window 50 floors up. "Lois! What have you done?!" Point: Superman and Richard Donner.
The exchanges are just more fun in Donner's version it's like a cat and mouse game that escalates until the eventual pay off in a scene that Donner, sadly, never shot. Reconstructed from screen tests, gaping with continuity errors, but it's remarkable the power that still underlines the moment when Clark is finally caught red handed, and removes his glasses. Subtly transforming from Kent to Superman right before our eyes it finally feels like the pivotal moment it should be, and resonates more deeply because the previous scenes support and sustain it. I guess what I'm getting at is, once again, the arc feels more natural, more complete.
Gone are as many as the throw-away Naked-Gunesque sight gags as Michael Thau could afford to cut. And what a difference that makes to the overall tone of the movie. Of particular note: the battle over Metropolis that finally feels like the epic brawl it should be. Other than a few additions, the major difference between Lester and Donner's version lay in the editing. And yet I cheered every time Superman sent one of the villains flying through a building or a sign as though watching this sequence for the first time I was thrilled when the villains created a powerful wind to stop the mob and the focus stayed on the destruction at hand cars crashing into buildings and other cars and not wigs and silly phone booth conversations. The villains are more threatening, more intimidating, and the battle appears more destructive now that their powers weren't used to generate jokes.
While I'm hesitant to say the humor in Donner's film is more sophisticated (the Donner cut does have toilet humor not present in the Lester cut), I will say Donner's jokes are better planned and executed. At least in his version most of them have proper build up and pay off.
Finally, the issue of complaints: were this another film under another set of circumstances, I would have room to complain. It does have flaws, yes. As mentioned above, the Richard Donner Cut of Superman II looks like a jigsaw puzzle that was finished with "whatever." Unlike Superman, Donner could not turn back time and finish shooting with the full resources he needed to do the job right. The disclaimer before the film clearly states it's a representation of the Donner concept. Nothing more.
Like I said, this is only a hint of what could have been. And that's more than we should reasonably have hoped to get.