I think that the discussion in this thread is pretty pointless. It is based on the common and naive assumption (or rather wishful thinking) that there must be THE perfect steel.
In a knife like the Caly Jr., isn't it completely irrelevant whether or not ZDP-189 has a lower Charpy value than ATS-34 or not? As long as the edge holds up (which depends a lot on what you are cutting anyway) and is not chipping out under you, the thoughness is obviously good enough. With a blade that is ground as thinly as the Caly's you are hopefully not prying anyway. No matter what kind of steel you are using, it would be trivial to break it.
And for a knife that you want much tougher, there are other steels, which are clearly optimized for a different usage....There is a reason why some steels are called "shock steels".
I think it is really necessary to evaluate a steel within the application (i.e. the type of knife, blade/edge geometry etc.) that it is used for. And even if charts and numbers give a good idea, in the end, time and user evaluation will tell, how good a steel holds up in a particular type of application.
