I'll also agree, blade and edge geometry make the biggest difference in the long run, so long as the steel itself has been manufactured and heat treated to decent standards. Some steels will take longer (or much longer) to thin to the best geometry; but once there, they perform a lot better and are easier to keep sharp. I used to be skeptical of S30V as a whole, but a couple of my knives (Kershaw Leek and a CRK Sebenza) turned my opinion around on that, after finally getting them to the geometry that made them 'work'. They went from yawn-worthy duds to amazingly sharp, once I finally crossed a certain threshold of thinness at/behind the edge.
The only knives in my memory, that I haven't been happy with, no matter what I've tried with them, were knives that displayed obvious issues with poor heat treat, after thinning them to realistic geometry. Edges just folded over under light pressure (one which I could SEE fold under pressure from my thumbnail), or burring issues were so bad as to make them almost worthless. I couldn't blame the steel type itself, as I have other knives in the same steels (from other makers) which are some of the best I've ever seen. Heat treat and quality of manufacture make all the difference, most of the time.
Another factor is finding abrasive types and even specific brand/stone types which work best with a given steel. That made the difference with the two S30V knives I mentioned above. I used diamond all the way for both, including 3µ Dia-Paste stropping on basswood, which made the night-vs-day difference on the Leek in particular. I'd previously kept trying to improve the Leek with other means, like sandpaper sharpening (SiC and/or AlOx wet/dry) and polishing with AlOx pastes (Simichrome, etc). But the edge on the Leek never fully responded until I took it through a sequence of DMT Fine, EF (& maybe EEF), followed by 3µ Dia-Paste, which put it over the top. With that experience behind me, I used essentially the same strategy with the Sebenza, using a Coarse & Fine DMT, and the EF, followed by 1µ Dia-Paste on basswood, for stropping. With the thinner geometry, I've since settled into using either the Coarse or Fine DMT (45µ or 25µ) for most of the touchups on that blade, with very minimal stropping to follow, and it's done a lot better than I previously believed S30V could ever do.
Bottom line though, with the exception of steels with heat treat or other quality issues, ALL of the knives I've initially not liked for sharpness have been improved, sometimes vastly, by taking them thinner than the factory geometry; sometimes much, much thinner. Thick blades and obtuse factory edges are too often a big disappointment, no matter the steel type or quality.
David
