Can't say for sure, but I can tell you about mysidia as my alt homes there. It is the unofficial jp server, and before the quake I have seen 100 + people in camp horizon at the same time. It not quite that populated since the quake, but I still see alot of players on. Wutai is were phil is at and there is a noticeable population difference, and wutai is said to be one of the busier 2 chocobo pop. Servers