I've recently tried a commercial monobath, after seeing information about monobaths in general and this specific product on YouTube. I'm floored at the quality of the negatives. I've used a homebrew monobath once or twice before, but the results were only "okay". This time, my negatives look as good as I've have expected from HC-110 Dilution G or H (softer grain than Rodinal or Dektol).
What baffles me, however, is that I can develop different films, say same brand ISO 100 and ISO 400, in the same tank, for the same process time, and both will produce good negatives -- despite the fact that normal development for the (conventional grain) ISO 400 is something close to twice that for normal development of the ISO 100. I'd usually expect processing "old school" (not tabular grain) ISO 100 film at the same brand's ISO 400 time to give me a two stop push (or N+2, near enough, in Zone notation).
I know monobaths produce a race between fixing and development; this is why most monobaths have shown some loss of true speed, because the shadows develop slowest and fixing tends to over take development for the least exposed halide grains. This is why monobaths have long been considered "niche" developers.
So how do these modern monobaths seem to ignore the "true" process times for different films and produce normal or very nearly normal negatives from films that would normally differ by 2x in process time for that result?