That depends on what you use as criterium to decide which platform is ahead. For me the best criterium is how much diversity of opinion - the only type of diver

That depends on what you use as criterium to decide which platform is ahead. For me the best criterium is how much diversity of opinion - the only type of diversity which really matters - is allowed on the platform and how much real interaction (i.e. not just shit fights) between those groups occurs. Currently X comes out on top in the former category while none of them scores anything worth mentioning on the latter.