I'm leaning towards a draw or Superman BFR's Nul/Hulk just like Thor did. I'm a little tardy catching up on all the Fear tie ins like the Dracula/Nul one shot but so far it looks like the hammers really upgrade the melee output of the worthy but does little for durability. Maybe Sin is the exception. Thing for instance had a huge upgrade in striking power but nothing was done for his durabilty(um...ouch against Thor). In Asgard, Odin told Thor that the Worthy's magic hammers were the most power weapons on Midgard so that leads me to think that Hulk can hurt Superman and easily at that.
I can't choose.. i don't like Nul but Hulk in my opinion beat's Superman but i really don't like Nul so i can't choose but i think i'll go with Superman only by BFR