Probably that the Schneider he's using has a hint more flare than the others - and doesn't want to admit that it is easily compensated for by a competent printmaker, at which point it'll be functionally indiscernible from the others, especially at the 6x enlargements he has admitted to using as a comparator. And there's no clarity as to what 50mm Rodagon - an f5.6, an f4 or an f2.8? The 2.8 is (in my experience) better optimised for bigger prints than the older, slower glass.
Personally, I've found the current Rodagons to be perhaps a hint (and we're talking a very small amount) better in their sharpness response in low contrast areas (the grain edges seem a hair sharper at fairly close viewing distances of decently big prints) than the Componon-S, but largely only in bigger prints (10x & up) & I am pretty rigourous about switching to the Rodagon-G at 15x, which does the job it was designed to do.
Wouldn't stop me using a Componon-S for non mural work if it was what I had at hand & I doubt almost any viewer of the final print would notice or care.