No reason to really say one would beat the other. The Hulk's fight each other constantly in Banner's subconscious anyway. Just as they can continually fight and get stronger indefinitely in the subconscious, they can fight indefinitely in the physical realm. Banner Hulk isnt weak at all...he held the 150 billion ton mountain range in the Secret Wars. Professor Hulk's base strength was above the other Hulks, although its suggested by other people that he wasnt. Professor Hulk was the biggest, smartest, and meanest Hulk that had been seen at the time. When he got mad he was awesome...i.e. what he did to Trauma, Juggernaut, and Hoarfang...This fight would continue forever except for the fact that these guys are smart and would realize there is no point in continuing.