By Clan Chat, I mean the new CC system that was introduced not too long ago.
Clan Chat:
[*]High range of ranks.
[*]Ability to have a Citadel.
[*]Ability to have "Rated" wars.
[*]To invite members to a Clan Chat, a ranked member must click on that person by finding them on RS.
[*]Use of own Clan Vexilium and Clan Cloak which can be customized (color, images).
[*]If you leave the CC, you need to be re-invited.
[/list]Friends Chat:
[*]Ability to have regular clan wars.
[*]Perfect amount of ranks for our ranking system.
[*]Disadvantage of needing to log on to the FC Account to rank people.
[*]Ability to have the FC Name to something like "War Today" to alert people that are unaware of such events.
[*]If you leave FC, you are able to simply rejoin and still keep your rank.
[*]Lootshare.
[/list]I personally rather the Friends Chat, it's way more simpler - all the Clan Chat perks that aren't available in the Friends Chat aren't all that great.
Oh and, I bet there are more things both the FC and CC can do, just wrote them off the top of my head.