Repeating myself from upthread, as someone who easts and enjoys both Sapporo Ichiban AND Shin (Red, occasionally black), the Original Ichiban (Red bag, predominantly soy flavored) is comparatively -neutral-. It works fine as a base, from which you’re free to add, and original has more flavor than the Chicken (never had the miso).
If I want something more neutral than Shin flavors to build around, it’s my default choice. In almost all other cases, Shin is going to be the standout in terms of flavor as the default, though generally it’s a bit more expensive (20% or so).
So it should be very different expectations. I’d never have Shin Black with seafood added as an example. Shin Red though, works fine. Original Sapporo Ichiban? Even easier. If I was adding some Gochujang marinated beef brisket, Shin Black would be best, with Original and Red being tied. Teriyaki chicken? Then Original, followed by Red, but not the Black.
So for me, the advantage depends upon what protein and/or veg I have in stock as to which of those options is best.