Most Helpful Guys
Since both are undead it's pretty much a TIE, since neither of them are going to ever stay down and stay dead for long. And neither of them can meet the specific requirements to defeat the other going by their franchise's canon, meaning neither can exactly "WIN" over the other. In an earlier Friday the 13th, think it was part 4, Jason was defeated regularly with repeated blows to the head with his own machete by a kid. Later this had been retconned in Jason Goes to Hell, that Jason Voorhees CAN ONLY be sent to hell by a blood relative. And even then Freddy can bring him back to life from that. The only other scenario that Jason can be defeated is if he is trapped under Crystal Lake because that was his original location where he had died, thus that's why there is a chain around his neck.
Michael Myers do not meet those requirements, if we went by Friday the 13th's canon. Michael Myers is also immortal because of a curse bestowed upon him according to Halloween parts 4-6's canon, and there isn't anything clear about how the curse can be broken, other than Michael would have to kill every single one of his blood relatives for the curse to break. Thus neither can really exactly "WIN" over the other, since Jason don't meet those requirements to break and end Michael's curse.
The fight would go on perpetually, at least unless somebody meet those requirements to trap and contain either one of them first or both of them. But even then they'll eventually be back and break free from their prison somehow some way.
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Let's go Jason, he seems more rugged and he has been through hell, literally! upload.wikimedia.org/.../...Jason_goes_to_hell.jpg
Most Helpful Girls
Jason Voorhees would in the end due to not being able to die but at most be in a coma. It wouldn't be easy though since both are basically tanks especially the one in Rob Zombies movie because that fucker is like 6'8
The guy with the human mask.
Although, both characters really suck ass. Both of them serve no real purpose other than killing people. Their movies BARELY cover the “why”. Or maybe I just don’t get it, but I’d really love if someone could explain their backstory.