Is it possible to run both of these plugins?
I suspect they are mutually exclusive, but I have found nothing to indicate this other than they seem to overlap in function. Maybe a way to require PayToBlog at registration and charge for a requested themes or plugins. How many people know when they register what level of Supporter they want or need. Maybe supporter can require a charge at registration time and then later for upgrades to themes and for additonal plugins?
It would be nice if there was some indication of which plugins do not work together by design as well as in practice.