Sorry, I meant the best server for population. Maybe a server with some mercs.
None of the servers that are currently available have mercs, AFAIK. I can say for sure that Carbuncle doesn't have any (thank ***)
I realize there's no "best" server but one that has the most people in it so I can join a linkshell and do events.
Any of the smaller servers have linkshells and you can do events with people. Thus: you don't need mercs.
I've long been an advocate for Carbuncle. We don't have mercs and hardly any RMT, which I consider a benefit and not a downside. You do need to talk to people and make friends to do content which is challenging to some people, but I also think it's a good thing, because it's a fun way to play MMOs so don't really see that as a bad thing either.
Anyway...if this person or anyone else who's deciding on a server wants to know, that's my $0.02. If you end up on Carbuncle, I've got a linkpearl for ya. There are a couple of fledgling groups that are working on endgame content you can join (right now), we regularly do all the Dynamis runs, and you can get plenty of help with things like Omen, Vagary, etc.