I belong to two guilds that both have FB pages. One used Yahoo groups but none of us could ever get it to work right. The one Guild opted for an open page--meaning all of us can post on it. The other has a closed page and only those designated as administrators can actually new posts (but anyone can reply or comment). Both use the page to encourage new memberships, tell about events, and remind about meeting. Having just been added as an admin on the one so I could promote an upcoming show, I would say it's worth it based on the amount of re-posts so far.
One thing I would add--when you have a closed, admin only page your guild must have someone(s) that are willing to frequent post and tag people. And when that person no longer wants to be in that position, then you need to make a way for them to "hand off" the job graciously.
We do not publish any one person's identifying information.