YOu are apparently asking about the substitute powders. NO?
If so, the cons include price, a much higher ignition temperature which makes them totally useless for flintlocks. The fact that once exposed to air, the powder begins to deteriorate, and lose its power is another negative. You have to use the stuff up the year you buy it, or it becomes so inconsistent that you cannot get good groups the next Fall.
If you order Black Powder by the case( 25 lbs.) you can get it still for about $12.00 per lbs. Haz Mat fees, and shipping included, shipped to your door. Good luck finding a substitute powder for anywhere near that kind of price. We hear of retailers asking more than $30.00 per can, and the cans don't hold a full pound of powder!
It also absorbs water from the air faster than does black powder, and requires modern solvents to clean it out of a gun.
Its a powder designed for those zip guns, with their plastic wrapped copper jacketed pistol bullets) That leaves plastic to be removed, again, by another different, and expensive solvent. If you use conicals, then you have lead deposits to remove in addition to the powder residue, and that requires a lead solvent, and a bore brush to clean the gun.
With Black Powder, and a Patched Round Ball, no lead touches the bore, so you don't need lead solvent. No plastic is used, so you don't need a different solvent to dissolve plastic. Water gets rid of the sulfur and the remaining charcoal, or carbon, and trace chemicals from the Potassium Nitrate with a little soap.
Oh, if you use them in a traditional sidelock percussion action rifle, you will need to buy more expensive #11 Magnum percussion caps, to insure ignition of the powder. The Standard #11 caps don't always work very well with these powders. The zip guns use all different kinds of primers, including Shotgun primers. All are more expensive to buy than are percussion caps.
Other than those observations, The NON-SULFUR powders are just fine. The slight odor of Sulfur dioxide that is evident when you first pour soap and water down the barrel is quickly disbursed, and is gone. Keep your nose away from the muzzle when pouring the water down the barrel and this odor doesn't even register on the map! If you use ammonia, or a cleaner like Windex with ammonia to clean the barrel at the range, or field, with a patch or two, the sulfur odor is gone, so that you can then do a more thorough cleaning when you get home. :surrender: :thumbsup: