In the Black Powder Reference Forum there is a large post of all the characteristics of the different powders available to shooters. What their good points are and even their bad points. All members were encourgaged to chip in and tell what they could with their experiences of powders. It might be worth reading for a person new to muzzleloading.

As for my personal experience with Pyrodex and Triple Seven Pellets, they were on sale one year and I purchased two boxes of each. The Pyrodex Pellets worked so well I purchased more of them. The Triple Seven pellets were a mass of hangfires, miss fires, flaming pellets, etc... I vowed never to (and have not) purchase them again. But this is one persons experience and you need to understand that. Others probably have excellent luck with Triple Seven. Maybe I hit a bad batch or a load that got damaged somehow.