John Moody, your descriptions have encouraged me to go ahead and try Buxom Beauty. I live in New Orleans, like A-L, and I can say that although blackspot is clearly a major disease here, powdery mildew really is not. It prefers somewhat cooler temps that what we have for most of the growing season, and frequent rain showers we receive also acts against the mildew. The only times I've ever had to contend with PM have been briefly in early spring and late fall. Having said that, I spray preventively for blackspot, because only a very few modern roses would actually look healthy here without it--I know some might disagree. But with regular --or even semi-regular-- spraying of Bayer Advanced Disease Control (the stuff with the tebuconazole in it) and occasional turns with Manzate, blackspot has been completely manageable here. So A-L, you might reconsider Parole/Buxom Beauty and see how it does.
Mike