Mike,
I think the best "bang for the buck" is the Chinese 12K. It is very important to finish lap it with 1500 to 2000 grit Silicon Carbide paper. If lapped well, it will take out 8000 - 10,000 grit scratches. The other stones mentioned above are good too. But, it is hard to beat the Chinese stone, if it is lapped well. This is coming from a guy that still has four Eschers...
I just finished an article for Knives 2014 that will show micrographs of how the edge is refined between 4000 grit and the final stropping. While I was doing the microscope photos, I was shocked at the difference that was made by changing the lapping on the finish stones. I will check with F&W to see if I can release a few of the photos.
0.5 Micron Chromium Oxide on Balsa will completely remove all scratches from a well lapped 12K stone. It is important that the Chromium Oxide just fills the pores of the Balsa, and is not a thick layer on the top.
Come up sometime. We will drag out the microscope, and I'll show you how things work.
I hope this helps.
Tim Z.