In my experiences Balmung is very friendly. Active endgame & active RP if you want to pursue either, and lots of people just casually playing to befriend. Low RMT. Etc etc.

The downside is it's hard to get on to. If you're in the US, I recommend trying at around 4am, and not on Friday/Saturday/Sunday.

Whichever server you pick, good luck and have fun in Eorzea