The niobium in S35VN also helps give it a finer grain structure.
Bottom line on S35VN: Tougher and better wear resistance than S30V. And from my personal experiences, better corrosion resistance, despite having the same amount of chromium, and despite the data sheet claiming it is the same for both steels.
In my opinion, S35 is the steel that S30 should have been. It's crazy how just a little tweak in the chemistry can make such a big difference.
Here, data sheet for S35:
http://www.crucible.com/PDFs%5CDataS...VNrev12010.pdf