I haven't really used any of the early '90 carbon damascus. I had thought to but snotwad wanted the knife pretty bad so I sold it to him. Those three above, I intend to keep in as new condition.
The Devin Thomas 110's I have have not got enough use for me to rate with a lot of confidence. I've only sharpened a couple of them once each if I recall correctly. With that experiance alone, I'd say something close to Buck's 420HC maybe slightly better.
Frankly, that's a real good question...where does Buck's two Damascus rate with other steels in edge holding? We know they cut like no tomorrow!!!