He is what he is, but he isn't what he used to be. How many versions of Kal-El, aka Clark (Superman) Kent have there been since he first appeared in 1938's Action Comics #1? I'm looking for the subset of canon Supermen and the differences between them, I'm not looking for a list of actors. For instance, after 1992's "The Death of Superman", he came back in several different incarnations.
P.S: Bizarro doesn't count.