You will have a easier start in bastok than the other nations due to it being easier to level. The first field book pages are for level 1 mobs. Bastok is the most annoying to run over to once you have op warps. Faster if you pick it. Second most popular nation on the server.

The most popular nation on by far. This does make getting all the OP warps usually quite a bit easier. The early exp is going to be a bit rough. 

Get ready for a trek. This is the least popular nation on this server and will have a hard time getting most outposts without garrison wins.