IMHO:
Coticule, smoothness 8/10, sharpness 6/10.
Chinese 12k, smoothness 6.5/10, sharpness 7.5/10.
Vintage thuringian and escher (same thing), smoothness 8/10, sharpness 7.5/10.
Coticule + chromium oxide paste, smoothness 8.5/10, sharpness 7/10.
Chinese 12k + chromium oxide paste, smoothness 7.5/10, sharpness 8/10.
Vintage thuringian/escher + chromium oxide paste, smoothness 8.5/10, sharpness 8.5/10.
This is defining smoothness as sort of the harshness of the blade on my face, and sharpness as how easily it slices through the whiskers.
I'm just pulling numbers out of my butt here based on how I feel about the finished edge and the shaves I've had off of the mentioned combos. This is by no means the end all, it's really just putting my feelings about the stones and combos into number form. Different folks will probably rate all of it very differently depending on their shaving technique and preferences and just their rating scale in general :shrug: Take it for what it's worth... not much :p
With regard to eschers and vintage thuringians... they are the same. Several companies mined thuringian stones during that time frame, and escher was just one of them. Some people think they might have selected the best rocks to put their name on, and maybe in general that's even true, but of the few vintage thuringians I have, and the one escher, I can't tell any difference. I've heard that the new thuringians, while still good stones, are not as good as the vintage stones. I think a lot of the newer ones have inclusions, but a good vendor should weed those out for you. Even the ones without inclusions, from what I've heard, are, again, good finishing stones, but not *quite* as good as the vintage ones. I don't have one myself to verify.