Superman's more exotic attacks like heat vision may have no effect on a guy that's so hot that he crystalized sand beneath his feat... in fact heat vision may make him more powerful.
Mjolnir conected with the front of Rulks head, and the side of his head, which left Rulk smiling. In Thor's hands the possiblity that Mjolnir can hit harder than Superman while being swung with two hands seems more than logical, and Rulk took this with a smile... he even caught the hammer one handed, before taking the fight to Thor.
Rulk unloaded on Thor as well sending him flying at incredible speeds. Superman would have his hands full will Rulk to say the least, not to mention that Rulk seems to be quite the battle tactician himself, I don't see what Superman's new disposition brings to the table when next week he will be back to his regular boyscoutish persona. Rulk however is a killer.