Apparently, the ability for Facebook pages to create groups may be coming soon.
Assuming this is true--which I'd venture to guess it is, since Google+ pages can now create communities--is it a good idea to set up a brand community on Facebook? Call me bitter, but as a person who once watched a useful and valued Facebook feature--the discussion tab--be removed by Facebook because they no longer felt it useful, my answer to this question is a hearty "no." (Shocker, right?)
As the admin of a page whose users had frequently used the discussion tab for over three years, and who watched that community and all the posts shared there disappear withno recourse or ability to export those archives, I have to say that I'd be pressed to ever recommend that a brand set up a community on Facebook. You have no control over what happens on Facebook. There are no metrics or tools for Facebook groups, other than a search feature that sometimes works/sometimes doesn't and the mysterious "seen by" metric. Yes, there is document and photo sharing in Facebook groups--but when your group members share those things on Facebook they grant Facebook "non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use any IP content that you post on or in connection with Facebook (IP License)." Not to mention that now
with Graph Search, all that content will be discoverable, and who knows how that will play out.
Why would you want to invest time and money nurturing a community on Facebook, especially given the dramatic decline in the effectiveness of the Facebook pages you've already invested time and money in? In my opinion, brands are much better off hosting communities in places over which they have control.