^I tend to agree with panthergod
Surfer is more versatile and can exploit a weakness (red Sun radiation). But such tricks wouldn't take Superman out of the fight or weaken him enough per unit time since yellow sun is still around. Surfer has the infamous board from behind trick that seems to always work and turn the tables. But the problem here is Superman has super senses and can sense the board coming from behind (if written well). Surfer tends to blasts and not so much avoid characters melee (he does avoid blasts at times through manuevering though). I take his stupidness of avoiding physical up close confrontations as due to underestimating a character or writer's stupidness.
Surfer has used exotic powers such as black hole blasts, use of shields, draining, etc. He rarely uses these though and tend to stay a primary energy blaster. Surfer knows how to phase but has never been shown to do it in combat (maybe because he or the writer doesn't think about it?). Surfer can see into the future but this power is impractical in a battle situation since it requires him to take time and concentrate.
Superman is less versatile. This is not really a weakness but can actually be a strength since his decision process of what to do is faster (he has less choices to choose from) and he can instinctively act at times without thinking.
Superman has faster combat speeds (not flight speeds) in close quarters and slightly better manueverability.
Superman is stronger and more skilled in h2h and can dominate Surfer in up close h2h battles. Superman tends to use his speed a little more intelligently and efficiently more than Surfer on average. Superman has other exotic powers like singing and t-vo but like Surfer he rarely use those exotic powers. Also Superman's freeze breath is not to be underestimated and can be used to slow down his opponent (nothing more). This creates a greater speed difference in the fight.
With that said, in character this fight can be a split or slight edge to Superman since Surfer doesn't quite avoid h2h melee very well. But if characters fought very intelligently then Surfer might edge Superman by staying away, exploiting weaknesses, and draining tricks to increase his own power and take away Superman's. But Superman is faster in combat and can catch Surfer eventually (if it's not too late). Superman's hv can definitely affect Surfer and be used to distract in order to catch Surfer. All in all a very good fight and one I would pay a lot to see.