Chris,one of the biggest issues with foam is any little breeze will make spraying it difficult. I suppose if you were to be walking every roof it could work. But me personally I like the mix to not even have hardly any suds at all, I think suds and foam trap the dead mold and doesn't pull the "dirt" off with the initial spraying and when it dries leaves it a bit more grungy than a non-sudsy mix. The mix can be thickened for sticking and cleaning properties without the use of sudsy soap. But that gets into a more personal preference thing I guess. And I do agree customers do like to see suds and foam when cleaning, no matter what it is. You guys in Florida also seem to work without the benefit of gutters to catch runoff, so I could see where foaming and suds do benefit some guys.
We tried a foamer for a while, it did seem to be more difficult to get it down on the shingle when the wind was blowing. Biggest issue we had was that it seemed to require more volume which increased the run off and reclaiming issues. It did produce the hang.
I think the "air" made the kill impact less because of the distribution. We had to do some touch up.
We did use it on out video for our website, which made for better video. Some things are for using and somethings are made for selling.