I have a couple that have basically surgical stainless steel and they can get real sharp. But usually the harder the steel the more brittle, and softer tend to dull quicker. A harder 440 or a VG10 IIRC are good mid-range metals. I have all these as well as a couple other higher end stainless and no carbon blades to speak of. l do have a small folding Damascus that wasn't cheap l like. l forget what SEALs favor, there is one that has titanium and no ferrous metal, so it is non-corrrosive and nonmagnetic, but a bitch to get sharp. l have a few different sharpening systems that work better on some than others, plus a honing stone for going old school on difficult knives. Sometimes you have to do in stages for angle and depth to get it where you want it. Never tried a strop, interested to see how that works.