Lex really should have learned Muay Thai.
To him, Superman is going against his own people in a traitor-like fashion.
Lex Luthor's puppet master quality bringing down Superman gives Lex Luthor an imposing side that will make even god-like being scared of him.
Lex is more than likely the more intelligent businessman between the two of them, but I would say that Banner is far more knowledgable when it comes to quantum physics and the like.
Has Lex made any suits that can take on Superman? I looked at it as a chance to do a story for the fans, a fun story.
Spider-Man and Superman defeat the warrior only by combining their powers and enlisting help from some native tribesmen.