Recently used three different brands of hose end moss & algae killing sprays on the roof from a ladder. All had potassium salts of fatty soap as the active ingredient because that was what I wanted to use. The Safer brand had 40% of the active ingredient while the other two brands plus one brand I didn't use only had 22%. Prices were about the same for all brands. The Safer and Garden Safe brands had nozzles that only allowed a fan spray to be used. The Bonide brand had a nozzle that could adjust from flat spray to stream and the stream position allowed the spray to reach significantly farther which was very important to me for the vaulted section of the house roof. I don't know if the Safer brand could be poured into a Bonide bottle and work properly as it's a "thicker" liquid than the 22% solutions.
If the Safer brand will reach everywhere you need it to that's the brand I'd recommend. If you need a spray that will go a farther distance I'd recommend the Bonide brand. I didn't use the Lilly Miller brand, which is 22%, and don't recall whether it had an adjustable stream like the Bonide brand.
Had rain once since spraying and dead moss came off all the roof areas sprayed with any brand and I haven't looked closely enough to say whether any brand worked better than another though I'd expect the Safer brand to be more efficienct since it's 40% instead of 22%.
Hope somebody finds this info useful.
Cheers,
BEH