LoyaltyLion Loyalty Program

This app has been fantastic so far, you really need to grab it while it is being promised for $19.95 a month forever for shopify customers.

Their customer service replies are superb and I am more than willing to wait anxiously for the facebook functionality and other features.

There is a little question mark? at the bottom left of the app where you can contact support - it lets you vote on ideas to come - very clean and fun interface

This page here http://feedback.loyaltylion.com/forums/217155-feature-requests also shows the requested features and their progress.

I highly recommend these guys.