The real reason to join up with a guild is for the Guild Level perks. But in all honesty, I've found the game has been more fun if you join a real guild that is active beyond board members. Sure it's fun to be all under the same banner, but joining an existing guild with regular members who log on all the time is pretty great for learning the game, planning events, and preventing the entire guild from fading when your leadership moves on to the next game.
Personally, I think setting up a chat channel for FoH related stuff and then having people join whatever existing guild they want is setting up for success more than board guilds. I mean, I have much <3 for Mistwalkers, but it always ends up with leadership leaving, then more people leaving until finally no one logs in anymore. At least an existing guild for years with dedicated long time members will still be there when the forum fad dies down.
Just my 2cp though
