Ok, I am odd man out on this one. I find that the Chinese 12K gives me a sharper edge than any of the coticules or thuringen/escher stones that I have. But... the coticule and the Thuringen/Eschers give a more comfortable shave directly off the stone.
The Chinese 12k is more difficult to lap flat and does require, for me, at least 100 laps but I like it so much that I paid full price for 2 of them. One is a backup, I never want to be without one.
Just my two cents,