Altough the Facebook algorithm (EdgeRank) seems to be the same for users than for branded pages, the truth is that it doesn’t work excatly the same way.
WHAT’S DIFFERENT FOR USERS AND BRANDED PAGES ON FACEBOOK (EDGE RANK)
1- The value of a fan like is barely pointless.
2- Fan shares are the most powerful way of engagement so we should encourage fans to do so. I would recommend you to measure viral reach and engagement as a key metric.
3- Fan comments are also very valuable but the brand needs to be present and answer comments actively.