Biggest issue: The form allows people to register without paying. Also, the payment page interface is ugly, with a teeny tiny little paypal button that can barely be seen. We have several other issues and things we don't like, but because I have to research and find a replacement plugin, I don't have time to list them all. If this worked the way we needed it to work, we'd not only use it but happily "DONATE" to it. Alas, it falls short of its promises.