I think Dio might win

Vampire dio has parasite powers which can take over people's bodies and assimilate their powers.

He can't assimilate their powers. Besides, Hisoka has a technique that resists mind control.

But what about that Jonathan thing? wasn't it for the sun fist thing or whatever he got, and thanks to that body it also helped gaining a stand or something? because tell me this, why steal his body if he could've killed him anyway, what benefit is there from doing that?

Dio stole Jonathan's body because Hamon negated his healing factor and reduced him to a head, forcing Dio to steal Jonathan's body. The benefit is that Dio will have limbs again to attack.

Never watched jojo, so...