I pick Arguello simply because his punch seemed to remain a very potent weapon even when he moved up in weight whereas Gomez definitely lost something the higher up he went.
I agree with Ezzards opinion , Arguello was a very damaging puncher even at over 140 , even at 34 yrs old he took a pretty solid Billy Costello out of there with one shot. I think Alexis knocked out a little higher level of competition than Gomez also.