I’ll third that.
I recently acquired a Naniwa 12k after years of finishing after a coti on either an oozuku, a vermio or recently a la lune to polish.
So far, relatively few passes on the 12k got me where many more passes on either of the naturals did. I have liked my natural edges, but always felt I could do more. The Naniwa edge looks much more polished under a loupe - quite different from what I see after the naturals. Not better or worse, just different.
I’m still figuring out how to best use the Naniwa, and the naturals for that matter. From what I have read, it can produce a very keen edge that might need to be softened a bit. Time will tell, but I now regret not purchasing that synthetic stone years ago. I could have saved a lot of money - probably not - HAD is a terrible affliction!