Since this was brought up in the Zulu v. USA thread....

We'll only consider H2H. I think there is little doubt China has the advantage in FFA.

As for the matchup, I have a similar viewpoint to this matchup as the Zulu v. USA

Zulu is stronger in the first 15 or so turns, though I think China is better able to fight off that super-early Zulu rush than the USA or most other civs (due to the plus one population)

China is stronger afterwards. Of course, it's not nearly as pronounced as USA.

For the Zulu to win, they have to either take out China early, or be able to gain a huge advantage through the Impi rush. If it's an even contest by the time the Impi rush is obsoleted, then China (and most other civs, IMO) is going to win.

The question becomes, which happens more often: the huge early Zulu advantage, or China surviving and still being in the game?

I'm inclined to say China, but I haven't been in enough of these matches to really provide evidence.