I plan to use Pyrodex in my percussion guns and the Grafs in my flintlocks.
Kurt - please don't use Pyrodex in anything. It will rot the bores. Use real black powder only.
I have used Graf's powder for decades, and it has always been good.
Conversely, back when Pyrodex first came out, a friend thought it was the best thing since sliced bread. However, his gun would rust fairly quickly, even after a thorough cleaning. He just couldn't figure out why that gun rusted so bad. The rust was so bad, he even named that gun, Old Rust. After quite some time, as my old friend was hard headed, we convinced said friend to switch back to black. Astonishingly, for him, the rust went, completely, away after a few sessions of shooting "old black". IMHO, Pyrodex is cancer to ML bores.
I have, also, had a few adventures with people, new to shooting black powder, whose caplocks refused to fire Pyrodex, under nearly any circumstances. The Pyrodex caked in the breech so bad, that the nipple and "clean out screw" had to be removed to pick solidified Pyrodex out of the bolster. In one case, the nipple was replaced, but the "clean out hole" needed to be left open to vent the gas from the solid mass of Pyromud, because the caked, former powder, would not ignite with the breech fully assembled. A jet of gas spewed from that clean out for roughly a half a minute before the main charge detonated. After the third time clearing this one person's piece, I gave up and handed my him my horn to use while shooting the course. He became a believer, in "old black" and bought a pound from one of the traders.