There was an article in Muzzle Blasts a year or so ago that tested the various substitute powder then, and rated them, for everything but price. Black powder is still the cheapest to buy. Pyrodex probably comes in second. Pyrodex is the oldest and most well know of the substitutes. Golden, and Triple 7 and any others you see, including some made by GOEX itself all burn at hotter temperatures, as does Pyrodex, compared to BP. For a Flintlock, you really have no choice but to use Black Powder.
Most of the subs omit the sulphur found in Black Powder, and use some other oxidizer than Potassium Nitrate. Most if not all the subs take on moisture from the air, and deteriorate after the can is opened, exposing the contents to air. Black Powder doesn't. Black Powder has an infinite life span, provided its kept cool and dry. If black powder gets wet or damp, it can be dried out, and it will still fire. The subs, once wet or damp, change chemically, and don't burn(fire) very well, if at all, even when dried. In spite of what anyone says to the contrary, the subs do corrode barrels, and do require the barrel and action to be cleaned after shooting, just as BP requires attention to cleaning. Because the subs are usually used in modern zip guns, and employ plastice wads, and copper jacketed bullets, you usually have to use modern gun solvents to clean them, to get the plastic, or copper out of the barrel, in addition to using soap and water to neutralize and clean out the powder residue. Black Powder can be clean with just soap and water. Both require that guns be oiled or greased, for storage between firings.
So the main difference between Black Powder and the subs is that black powder is cheaper, its no longer available at your local sporting good store, because of storage regulations, but can be shipped to you directly, at a substantial price savings; all the powder measures and loading data are listed for real black powder, so you don't have to convert anything, and black powder has an infinite shelf life.
The subs are much more expensive to buy, although available at your discount sports store, will not work in flintlocks unless you also use black powder to help ignite the sub, has a limited shelf life, and has to be loaded by volume, based on the equivalent volume of real black powder.
Some of these powders are so new that sufficient use of them has not yet occurred to generate data from more than one lot of the powder to see how consistent the powder is from lot to lot.
In Black Powder, there is only one US manufacturer, and that is GOEX. If keeping jobs in AMerica is important to you, buy Goex. We can also get Swiss powder, made in Austria, I believe, and we can get Wano, Schuetzen, and Graf& Sons( company brand) powders, all made by the same company in Hungary or the Czech Republic, if I recall correctly. There is a Chinese made powder that is available in Australia and New Zealand, but I can't remember its name.
The Swiss powder is generally consider to be the " Hottest", ie., creates the highest pressure and velocity, of the powders. I think Golden and Triple 7 are fighting it out for the fastest velocity producing sub powder.
I have never seen Golden for sale anywhere, although its obviously being sold. I asked all over Friendship the first year it was out, and no one had any. The same thing happened a couple of years later when Triple 7 came out. Now that it costs about twice what I pay for black powder, I am no longer interested.
