For me, it's about knives, more than steels. So far, almost all the Spydercos I really like come from Japan so my steel choice is most often between VG-10 and ZDP-189. The midlock version of the Sage may change that, when it finally arrives, but for now, the only S30V knife of mine that sees any use at all is a Native. On the other hand, that Native is my beater and loaner, so it has seen a fair amount of resharpening. I'd rate ZDP as noticeably better when it comes to edge holding, but more time consuming to sharpen. That in spite of the fact I've never allowed either of my ZDP users to get really dull, while the Native has been returned to me with a "child safe" edge a couple times. I I'd also say they perform best, at least for me, with different edges. ZDP with a very smooth edge, S30V with a much coarser, toothier, one. I'd rate S30V as the more stain and rust resistant, and ZDP-189 as the more scratch resistant of the two, although neither is really "less" by all that much.
As with most things in life, YMMV.
FWIW, William Henry was the first US maker to use ZDP-189 and Blade magazine did a write up of their thoughts on it, and Sal's, in their February 2005 issue. Here's an excerpt from it.
To test ZDP-189, William Henry Knives sent one of its model B15 folders with the steel to an independent source. According to WHK’s Rick Thronburg, after 100 cuts through 1-inch manila rope and with the edge still cutting well, testing was concluded. By comparison, here is how some other steels performed in the same test:
•440C: 15 cuts;
•154CM: 18 cuts, and;
•D-2: 30 cuts.
“At some point in the future, we will run the test again to see how far beyond 100 cuts ZDP can go,” Thronburg noted. “But for now, ZDP-189 so completely eclipsed the performance of conventional steels, we had our answer.”—
by BLADE® staff