This is a clear, concise and easy to understand blog post on the difference between Facebook pages and Facebook Groups.
I think because it is a table format it makes it easier to glean the information. I love tables and you can add tables to your blog with the right plug-in or if you know code stuff you can put one into your blog post.
But that is another post discussion. Here is the great post that shows the differences between a Facebook Page and a Facebook Group.