I am currently in the process of working with some 52100 and some Hitachi Blue #2.
I still have some O1 on hand and a few completed knives in O1. Not real sure how much I will be using it though. Something in my body chemistry has changed and whenever I touch an O1 blade it develops rust spots in a matter of hours. I knew some smokers that could do this when I was working as a machinist, but I do not smoke and can't figure out what causes it. The Super Steels are actually not that much more difficult to sharpen. I can put a thinner edge on the higher alloy steels than I can with O1 and consequently there is less metal to remove to do the sharpening. It is likely I will use more O1, but it will not likely be on a regular basis. Same goes for the 440C. I liked the steel and had good performance from it, but just did/do not feel there was a strong enough market for it.
I do have high hopes for the 52100 and the Blue #2 though. I am making a couple different test blades at first to check out edge geometry and performance.
