Black powder for most applications, the fouling issue is exaggerated for civilian sporting use. Hunting out to 300yd isn't really an issue. If you can't get within a quarter mile of something... well, lol. It's cheap (if you make it) and it's easy to clean. Because all powders require Hazmat now, the price difference between BP and "subs" isn't really all that much. Due to the pressure impulse, it's also the ideal powder for bore-sized projectiles in a rifle (whacks 'em in the butt and makes 'em fill the grooves quick).
If I'm not going to go simple with BP, I'm not paying for "subs" that cost the same per pound or more than standard smokeless (and you use notably more per shot than with most smokeless powders = $$), yet are not nearly as capable as standard smokeless (for the weight), and still foul nearly as much as BP (except BH209, which is like a "dirty" smokeless). Then there is the cleaning issue, with all of the BP "subs", you need to clean them after shooting; but modern primers and smokeless, you can shoot all year and not clean it once with no issue. Less charge weight for the same velocity= less recoil.
Want something more like BP (for less$$$), use Red Dot through Herco; want something a little more like BH209, use H4198 through Reloader 15. Then there are even slower powders for FPS and big bullets with big animals (grizz, Buff, Elephant, Rhino, Hippo, ect). That being said, every land animal on Earth has been taken with BP guns... so you really don't need super-duper FPS.
As you can see, I don't understand the draw to the "subs".
* : obviously in a Smokeless capable gun.