The May issue of Tactical Knives contains a letter with the same question ( A-2, ATS-34, VG-10,440C and AUS-8.) Your 440C and ATS-34 were the tops for corrosion resistance, while A-2 was listed as the toughess. My small collection has a representative for all the basic steel families. Naturally Marine knives are S/S. The only specific steel I ever sought out was a high carbon, 60 Rockwell Swedish Mora. This is the only combination that will produce sparks with natural lithic materials ( and having done so, I bought 3 more disposable Bics.) Many knives now come with a protective finish such as epoxy powder coat or a phosphate parkerizing. Do not overlook oiling the edge on these. There are oils and waxes, silicone cloths etc. Don't make my mistake! Italian hard sausage is rarely improved with gun oil !