Unfamiliar with FFXI, however, have played DAoC since it began.
I would suggest starting on Gaheris unless out-of-game comments and stupid names drive you crazy. Gaheris is a cooperative server; that means there is NO realm-versus-realm, however, you can try-out any character from any realm and travel to any dungeon regardless of realm. That way you can see firsthand what character seems to fit your style. You'll want to join a guild, too. It's a great way to get information from folks who actually play the game. (Also, they're likely to help with items and groups).
Then, once you get the feel for your character-of-choice, you can start over on one of the other servers. Mordred is entirely PvP. Percival, Nimue and Guinevere are role-playing servers--no out-of-game chat in public chat windows. The rest tolerate movie and sports talk and all have battlegrounds and an RvR frontier.