Facebook announced that the "like gate" option will no longer be approved , as of November 5, 2014. We think that the "Form Gate" may survive. We think so because it requires a person to "opt in" for contest without requiring the same persons to "Like" the Page.
We suggest using TabSite for your contest applications. They will reliably keep you informed on what can and can not be done, and give you the tools to make it happen.