The "loses initial sharpness" thing is one that comes up frequently over the years in reference to all sorts of steels. Ironically in this case I've also seen many people say it about ZDP-189. Until there is some clear pattern or a standardized test I can't take it any more seriously than anecdote. Perhaps if people only said it about coarse carbide steels and not fine carbide steels, or only when comparing steels of different hardness. But the only trends I have seen are bias and placebo.