features will depend on server,
but MAINLY a GvsE will be based on 2 teams/factions (good / evil) which you will choose at login or u will be automatically distributed.
some servers got noble auto, or u must make it.
some servers allow u to make subclass, some others not.
clans can exist or not, since is a 2 side already choosed (good/evil) again depending on the server.
some servers will put you farm for adena, some will put u pvp, each pvp will give u adena/currency to buy ur gear.
some servers will allow u to pvp with ur faction (good/evil) too, some will allow u to do that only with the opposite faction.