Howdy Mr. Iron!
There are a number of powders out there and each of them showcasing something unique to set themselves apart. The main differences are going to be either a formulation/recipe or fit/finish. Both will affect how the powder burns and result in different 'power' and different fouling! The main recipe factor most folks talk about is the charcoal source (which wood is used) You can imagine that different woods behave different when burned. Some are cleaner, some are more energy dense, some burn faster, etc. The recipe also will dictate how much and what type of fouling. Some powders create softer fouling, some harder fouling.
The other half of the powder discussion is the processing it goes through. We use the 'g' rated powder (Fg, FFg, FFFg, etc). there is also 'a' powders (Fa, FFa, FFFa etc). The 'a' powders are less refined, less consistent, not polished. This is common in fireworks and blasting powder. Our powder is polished (each manufacturer to different extents) and may even be lubricated with something like graphite to help the powder pours and flow through horns and flasks. The granulation sizes are 'ballpark' as it is 'screened' and the quality of the screening process varies by manufacturer. I believe Swiss even makes something called Caviar Ball Powder where they polish their powder to very consistent 'balls'.
I am not experienced with all the manufactured powders out there so I dare not enter the fray as to which powder is best for you. Only to say that as with all thinks muzzleloading, it's best to try out what works best in YOUR firearm.
All the best!