Just being able to view the pictures in full resolution would be reason enough. Add to that... being able to view the videos, the increased number of posts you can make, the ability to remove photos you decide to and comments that aren't proper, AND the ability to exchange pics/vids privately thru the message system.
I can hardly take the wife out to eat at a nice place for the cost of a year's premium membership so I consider pretty cheap entertainment and certainly worth the money!