Godzilla, primarily out of fandom association, secondarily due to the fact that kong winning would likely just be due to some senile executive making some random claim that kong is the more loved monster (which isn't really true). and thirdly due to the fact that we've already seen kong win
I was always more of a Godzilla fan coming up as a child. I watched a lot of those old Japanese flicks on him destroying cities and wrestling with other titans.