You'll have a larger quantity of combined W+V in SRS-15 vs. just V in R2. In addition, R2 will have more Cr than SRS-15. The greater quantity of W+V on top of the lesser quantity of Cr should result in lower corrosion resistance as well. For what it's worth, I only have one knife in SRS-15 and several in R2 and I anecdotally find the SRS-15 to be less tough at comparable edge geometry than my R2 knives. In all likelihood that's tied in more to specific heat treatment of the two steels, but I'm no @Larrin so maybe he wants to chime in. I'm not trying to say it's a massive difference, but there's more of a compositional difference between the two than, say, 52100 and 1095.