...Back on topic, I have to say that General Zod is now, to me, the definitive "Evil Kryptonian". His portrayal in Superman II has made him eclipse Jax-Ur as the most Evil of Kryptonian Criminals.
As crazy as I am about the Phantom Zone criminals (some of whom were not really "evil," like that Mad Prophet of Argo City and that monster-thing) I have to admit, General Zod received very, very kind treatment in the movies: in the comics, he was the unfortunate victim of "hey, that Kryptonian is my exact double" story, though that business about the army of clones was pretty cool.
The movie did him a real big favor. Now, when you think of General Zod, you think of this powerful, charismatic figure that scared the bejeesus out of you when you were five.
I rationalize it a little this way; though a great genuis, Lex early had contact with the Legion of Super-Heroes, and later, the Legion of Super-Villains and Brainiac from Colu. In each contact with superior technology, he had the smarts to see some new underlying principles and apply it to his own technology, Ditto with Lexor. And there was one story where Luthor and his men shrank down and took over Kandor---I'm sure he "borrowed" from Kryptonian technology also.
Good rationalization; I had forgotten all about the "Lex rules Kandor" story. Something like this incorporates a character into a background a lot better.
Though here's something to bake the noodle: what if the reason some of the Legion of Super-Heroes' 31st Century technology exists, is because Lex Luthor invented it? But...the way Lex Luthor invented it was because he found it in the 31st Century?