Has anyone used the PunchTab loyalty program on their site?

I recently used Punchtab for a Giveaway and it worked really well. Their Loyalty program seemed interesting and I have thought about adding it to my site but i'm still not sure about it.
I don't want to add it and have people not use it, hate it, or just be confused. Has anyone else used the PunchTab for the loyalty program? Is it working well?

See original post by TrueVapor