Two years ago when I got into muzzle loading rifles, I was at Friendship and didn't know which powder to buy, so I bought a pound of FFFFg (Goex) for priming my .50 caliber flintlock Pennsyvania Long Rifle plus a pound of FFg Goex because I had heard that for .50 caliber and up, one should use FFg powder.
However, a good friend and shooting buddy of mine who initially got me into traditional muzzling loading rifles recommended using FFFg, so I bought 3 pounds of it (Goex) as well.
To make a long story shorter, I've never opened the Goex can of FFg because the .50 caliber flintlock plus the two .50 calber Hawken rifles I now also own all shoot very accurately with FFFg. Another shooting buddy recommended Swiss black powder over Goex, so I now have a half a can of FFFg Goex left plus 3 pounds of FFFg Swiss plus most of a pound of FFFFg Goex and that unopened one pound can of FFg Goex.
And so... it appears I've got enough powder to last through this summer's shooting... and possibly longer.
As to whether the Swiss black powder (at $22 a pound) is better than the Goex (American-made at $14 a pound), I'm not sure... but it seems (so far) that my three .50 caliber black powder rifles (the Pennsylvania flintlock or the two Hawken percussion cap rifles) all "like" FFFg just fine and all 3 are very accurate with target loads of FFFg Swiss.
As others have pointed out, the FFFg black powder yields high velocities with less powder than the FFg probably would, but I don't know if that claim is true or not since I've never attempted to use the Goex FFg powder... but I plan to find out this year when the weather becomes more "friendly".
Strength & Honor...
Ron T.