Never use Byzantines because of one reason
their building has more HP this will cause u to build slower and since the dont have the crane upgrade they r horrible.
Chinese pwn because of Chu ko Nu and cheaper technology
Many people say that Chu Ko Nus are weak but they r not
if u have 40 Chu ko nus(cost around the same) and 20 paladins the chu ko nus will win. the trick is 2 use them in numbers. they also r trained faster 2.
the chinese also start with 3 xtra settlers this gives them an early boost on the economy(time 2 train settlers)
i think the best civs r
Truks Chinese Huns Teutons