>>115918635HIM wins. Here is my logic.
HIM while he occasionally gets beaten up by the PPGs is often depicted to be powerful enough fight them off or even win such as when he took over the future. A lot of the time the girls don't outright beat him in a fight instead just ruining whatever plan he had. So being on par with the PPGs is much more impressive than Aku losing frequently to Jack who is much weaker and slower than the PPG.
While Aku resists physical attacks he has been defeated by spirits such as the elementals. HIM with his reality warping might be able to find a way to harm Aku like the elementals did.
Basically HIM scales to much stronger characters than Aku or Samurai Jack and his reality warping abilities could probably bypass Aku's durability and regeneration.
