I make about half my knives out of D-2; the rest are 154Cm with the odd one in S-30V now and then. All three are excellent steels if heat treated properly. My current experience with D-2 and S-30V rate them about the same in edge holding; we talking about in almost identical blades here. Both of them are very tough steels. D-2 will rust if used in a humid environment or kept in a damp sheath for too long. S-30V won't. While rust on the sides of the blade is no big thing, when the edge rusts, there goes your edge holding. I recently had a customer using one of my knives in 154Cm and a Dozier knife in D-2 on a south Texas hog hunt down by the coast. He reported that the Dozier did show some edge rust on the second day of the hunt. What it would boil down to, to me, is using a blade which requires a bit of maintenance(D-2) or one that is maintenance free(S-30V). Outside of that, both are excellent steels.