Now I've used vB and IPB. In IPB, they ask you to put in the IPN, unlike what it seems to do in xF and vB, which I don't know the difference why one subscription service would want the IPN and the other just the email address. If I remember correctly from when I was on vB, their system worked much better. My questions are: 1. If someone decides to try to change the amount they pay, say the subscription is $10 and they "hack" it to change it to $0.01, will xF check to see what they actually paid and if they didn't pay the right amount, would it not upgrade them? 2. Is it able to automatically handle disputes? Such as removing the upgraded status. I could have sworn vB's system did that but I don't remember anymore so I could be totally wrong...I just know IPB's system doesn't do that.