Well I'm not a super expert on every single comic book, tv series and what not ever written, so I didn't know he could stay in Hulk form forever. Every single Hulk show I've ever seen, he's always transformed back. And while he was the Hulk, he was never super smart, just pure emotion. Sure the guy playing him was a genius, but that just disappears when he transforms. That's the problem with all of these debates. Which one is the defining series to be used as a comparison? There are so many different versions of each character with different powers, you can't really fairly compare. In the end it just comes down to whom you like better.
I'm sticking with superman. He just has WAY more powers than the Hulk. The superspeed alone will keep the hulk from ever being able to even land a punch on superman. That's the biggest problem I've always had with the way they write superman is that he didn't use his other powers more effectively. The guy is sooooooo fast he can reverse time, but he lets normal speed people punch him in the mouth? Yes, I know we wouldn't be able to follow along with the fights or be entertaining if he did use his powers effectively as he would slaughter everyone... but come on! You give him all of this power and yet he only uses about 10% of it to win fights. And he'll keep it close for entertainment value and risk losing his life and all of humanity as a result of using a small portion of his powers... when he could easily wipe the floor with any of these guys if he used them all.
He also has laser eye sight and should be able to just melt anyone in his path in two seconds. Also his super power breath could keep anyone from getting anywhere near striking distance of him, etc. Just freeze everyone into an ice block. Freeze the hulk till he calms down, or throw him in the sun. You don't even have to beat the Hulk, just use your super, time-altering speed to grab the guy and throw him into the sun before he can even blink. Even if the Hulk can walk on the sun and survive there, he ain't goin anywhere! Superman will be the only guy who can go and get him, otherwise the hulk can't fly back....
Or throw the Hulk into a black hole. Not even the hulk can withstand that kind of environment.
And also I do remember a plane taking the Hulk into space in the last movie to knock him off and the Hulk passed out and froze while the plane was falling apart... Superman totally can survive that atmosphere. I mean seriously, there's just sooooooooo many ways that superman can win this fight. It's a no-contest.
Brute strength is nice, but that alone can't win fights like this.