It's a fantastic powder for .38 and .357 in most handgun-length barrels. A load near published maximum will reach the practical terminal ballistic limit of either of these cartridges, and it will do it with less recoil and a great deal more efficiency than the "magnum" powders like #9, H110, Lil'Gun, 296, Enforcer, 300MP, or even 2400. Those magnum powders will certainly deliver more velocity, but in 4" and shorter barrels, it will only be a little bit more and with no practical effect in terminal ballistics -- 50fps, or even 90fps just isn't going to kill deader. The difference they make in velocity is most pronounced in carbine-length barrels and a couple-hundred fps can make for a flatter trajectory for a given bullet weight if nothing else.
BE86 has the kind of burn rate that most of it is burned in a 4" or even 3" barrel. This isn't true for a powder like H110 where only half a full load will burn before the bullet exits the muzzle, resulting in a lot of flash. So BE86 needs a flash suppressant less than 2400 or H110 does, but it has it, and those other powders do not.
BE86 is also inexpensive. 8# was selling for around $134 (when it was available). That's about $25 less per 8# than comparable ball powders, some of which need loads of two or three-times the mass. It's not as cheap to shoot as those fast powders that only need three grains for a load, but as a high-performance powder, it's more cost-effective than powders like Blue Dot, 2400, Longshot, or HS-6. It's a lot more cost effective than the magnum powders.
Power Pistol is very similar. It delivers a little more velocity, but with no flash suppressant.