Dean Cain's Clark is by FAR the sexier of the two personalities. It all comes down to how he plays the role - such warmth, such utter humanity, and there's a really fun-loving side to Clark. You don't get that with his Superman self until Season 3, once Lois knows about his secret...but then, it's always on a one on one with Lois. And as much as I love the Lois and Clark interactions on the show, I equally love how the Clark side of him interacts with ALL of the people around him - Jimmy, Perry, Cat, various other one-shot characters. We never get that same, approachable personaility when Superman is talking to Perry or Jimmy.
Yeah, Superman is hot and all, but I'd take Dean Cain's Clark any day of the week.