As I see it Goex’s Olde Eynsford is the best. It’s energetic like Swiss and Triple 7, but costs barely more than a dollar over their standard powder. This means I can chose to use the same charge and get more bang or reduce the charge to get something similar with less powder that either brings the cost to equal or maybe better. And at the same time it fouls less. I’m a hunter that really wants to have my rifle and revolvers using the same powder flask, and since the revolvers are the lowest denominator here it means I need a high energy powder where my Remington revolver has enough oomph to rely on, in this case I’m on par with a standard .45 ACP or .45 Schofield level and not a .38 Spl or something else dismal.
However I want my guns to shoot well. It may mean I have to try 2F instead of 3F as I believe my revolvers will still do well enough, or maybe it’s Swiss, a powder I want to try anyway. I’ve used T7 in my pistols but think I’d prefer real black powder as it’s more consistent if nothing else.
For a rifle having an energetic powder isn’t an issue though. So it comes down to fouling, if that’s an issue, and the lengths to which you’ll go to get it. Do you want to be able to get a pound locally? It’ll cost a bit more per pound this way. I used to use T7 as it was the only energetic powder I could find locally at BassPro, and hour there and back. But all things shooting were hard to find, and for months no 3F so I got tired of wasting my time and looked online. Sure, I had to drop a bit more coin upfront, but what I found was ordering 3 lbs at one time broke even despite shipping and HazMat, but I didn’t have to go get it so it saved me gas @12 mpg and time, not to mention frustration. I buy from Grafs since you don’t have to purchase in huge orders. Anyway, there I found Olde E and been buying it since, which is cheaper than T7.
Quite frankly you could shoot re-enactor grade powder. Inconsistent from what I have read, but some find it works well enough.