I've been carrying a Dwyer Custom SNG in "VimCru", also known as Rex 20, or M62. It's in the High speed steel, or "very high speed steel class"
http://www.crucible.com/PDFs%5CDataSheets2010%5Cds20rev1%202010.pdf
The knife itself is built to a very high standard, and well finished. It came sharper than the regular SNG line, but it's still no sushi knife. I picked a V grind model as I can't stand the chisel grind , which was another option.
The Lockup is very good. Tolerances seem tighter than stock, which is to be expected.
The only drawbacks were 1) it came with a bit of corrosion starting in early stages adjacent to the opening hole on the blade. My guess is the knife had a fingerprint left on it which caused the tiny blemish.
2) The steel isn't anywhere near the hardness it could reach. I understand not running it at max but I feel 3 points higher would not compromise this and it would be an even better performer that it is. IT could be me though. I just like trying to get every bit of performance out of a blade as I can. I'm not a guy who is going to be batoning a SNG, nor prying with it. I have much better tools for that. I use knives to cut, so to me the higher hardness the better.
I did e-mail Dwayne to ask him a question when the knife arrived. He promptly responded with his Cell number and told me the best hours to call. Though it was just about the rust, and not of any import for a user I was very impressed by his quick response.
I'm going to keep the knife and use it as intended. Anything less would be disrespectful IMO. He made a great knife, and seems willing to stand behind it so that makes me comfortable keeping and using it.
I haven't even begun to explore the limits of this steel yet. I'll take my time doing so, and enjoy it. It does cut nicely, and sharpens easily. I'd liken it to a beefed up M2 steel more so than even M4. Still, it leaves me wondering what it would do at RC 66 instead of RC 61.5.
He's got some really interesting knives on the market in some pretty rare steels. For my pay grade they are expensive. Do I have any buyers regret? Not one bit. I look forward to a long and happy relationship with this particular knife.
If he had made a Rex 121 model in V grind I would have that instead.
Now ask me in a year or two how I like the knife. I'll have it figured out ( the steel , hardness, finish combo) by then.