Basically what cudarunner said. Naturals are a crapshoot, there are people with the Chinese "12K" that can't get anywhere near a 6K edge off the hone. Not all of them behave the same. Some are medium grit and not at all comfortable to shave with, some have inclusions that make them unfit for honing (or need to be dug out).

Barber hones are something of a crapshoot too. You'll notice most aren't graded by any form of grit rating. But usually you can count on them being somewhere in the 8K ball park, some a little higher, some a little lower, but most will leave you with an edge you can shave with if the hone's in good condition. A barber's hone will also get you where you want to be faster. 5-10 strokes on a barber's hone every couple of weeks and your edge will never need to see another hone. If you've got a good Chinese 12K, I'm willing to bet you'd do 10x that amount at a bare minimum when you need a refresh. I usually do more along the lines of 150 to 200.

Knowing what I know now, if I lost all my hones in some horrible boating accident and was given the choice between a barber hone and a Chinese 12K...give me the barber hone.