Key Feature Facebook Page Facebook Group ???Ugly??? URLs No Yes Hosting a discussion Yes Yes Discussion wall, and discussion forum Yes Yes Extra applications added Yes No Messaging to all members Yes (via updates) Yes (via PMs) Visitor statistics Yes (???Page insights???) No Video and photo public exchange Yes Yes ???Related??? event creation and invitation Yes No Promotion with social ads Yes (never tried it) No
Interesting comparison of the core differences between a fan page and a group page on facebook. Key difference is the ability to message the entire group.