Re: Gene Hackman or Kevin Spacey?
Spacey's Luthor had a more manic edge, while Hackman's take was more sardonic.
Spacey seemed to be genuinely close to insanity, while Hackman seemed like a mortal whose dreams exceeded his grasp (barely). Since Lex is eventually elected President of the United States in the comics (I believe), I think Hackman's was more believable.
That being said, I enjoyed Spacey's performance more than Hackman's mostly because of the bigger scope of his plot and range.
In the beginning, the universe was created.
This has made a lot of people very upset,
and has been widely regarded as a bad move.