I have a pair on my 629 DX. I don't know all the factors that go into the extra cost; I'll just offer my opinion:

-They're imported.
-They use state-of-the-art computerized tooling to cut the things; the fit has to be seen to be believed. No gaps or loose spaces anywhere -you couldn't fit a hair between frame and grip(well, that's exaggerating a bit, but not by much)


Other than that I don't know what to say. The finish, while well done, doesn't seem extraordinary; nor does the wood. In fact, the first pair they sent me I had to send back because it was the absolutely worst-looking piece of walnut I've ever seen! It looked like pallet material -I kid you not. The pair they sent to replace it was satisfactory. I wasn't able to get a smooth pair, though; I had to take what they call a "stippled" grip, which serves the same purpose as checkering but is uglier(I don't like checkering -stippling is worse).

You've probably gathered that I don't think I'll be getting another grip from them, but do as you like; many folks really like their Nills.

Andy