David Weaver
...I bought a gaggle of synthetic stones, but left playing with them too early to see these (presumably private label vitrified stone made by someone like bester).

Interesting review - what I take from it based on experience is that it's more coarse than a shapton 5000. The chosera is an oddball - it's a fine gritted stepping stone for knife sharpening. IIRC, about 3 microns and soft.

Same for the shapton 5k - something like 3 micron.

There's not much free lunch in synthetic sharpening stones, but I saw many promoted by gurus (not commenting on the suzuki stone) promising one. If it's faster and finer, it'll be softer. If it's faster and same hardness, it'll be coarser.

At some point, one of the knife suppliers made a dizzying array of what I'd call $50 stones but for about double that because they offered three hardnesses at each numerical rating.

Probably a direct comparison to the suzuki 4000 would be the chosera 3k, which is still even a fine stone (4 micron).

I've cast off most of them, though, and use an oil bath (crystolon and india stone) for coarse work, even on japanese tools. Those two don't stay that flat, but do fast prep (can be blindingly fast with the crystolons if not careful). I find that the very hard japanese tools don't mind that regimen unless they're overhard (the edge may crumble, but that's a tool problem, not something to coddle as the tool will punish a user each time it chips - interestingly, the unicorn bevel that we're talking about here is protected for overhard tools).

Anyway, I've seen the same thing with the scope - what looks less coarse and more matte can look similar under the scope. When stones get close together in fineness, it can be very hard to see a difference except to look at the very edge of the tool.