The goal is to have a chisel that does neither without treating it tenderly,  which is apparent to anyone making stuff. I have been using David's chisels for some time now and the edge is the most durable of any chisel I own for the work I do in cherry and walnut.  No doubt misused these high hardness chisels could break.  Used normally they don't.  David worried about corners chipping but they have not in my hands.  And they don't deform like any softer chisel does in my hands. High hardness is essential to resist deformation.  The trick is to get high hardness while preserving toughness.  

The bottom line is that David's research and experimentation has produced an exceptionally durable chisel that can be readily sharpened by anyone not stuck in ancient sharpening technology.  What's not to celebrate?

One would hope that the details provided will encourage someone else to replicate this work.  David's success should be sufficient motivation.