Update: Having learned the lesson that you get what you pay for a hundred times over, I figured I'd take a chance and give the relatively inexpensive vise found on Amazon a try. Every once in a while you get lucky. The vice itself was fine, but the rubber base was very soft and did not provide enough support to keep the vise from vibrating when hammer & chisel cutting. Might be OK if using pneumatic and your non-cutting hand is supporting the vise, but a no-go for H&C.
So back to Amazon it went, and I found this made in USA vise from Pepetools (link below). This vise is fantastic and while nearly three times the price, still considerably less costly than the similar model from GRS (I believe it is comparable to the GRS Standard Block). It has an attractive wood base that is lined on the inside with a thin felt material that provides enough friction to steady the vise, but allows for easy rotation. I'm very happy with it and my engraving improved overnight as the result of finally having a proper way to hold the work. I have never used a GRS vise so I can't provide a direct comparison, but this vise seems to get the job done well.
As an aside, I'm not sure but I suspect the GRS vises might be foreign made, as identical vises marked GRS are available on the grey market (eBay) shipped directly from Asia at a steep discount. But those could be knock-offs and I didn't want to take a chance. One seller I questioned indicated they have a rubber base. Not sure if that rubber base is any better than the one from Amazon or the same as the genuine GRS, but I'd be surprised if they come any stiffer than the wood base from Pepetools. The only downside I could see long term would be the felt possibly wearing out, but that should be easy to replace should it ever happen.
I have no interest in plugging the Pepetools vise other than to share what I consider to be a good find at a reasonable price if anyone else happens to come across this thread while looking for same. Gesswein also sells the same vise for $4 more, don't know if they charge any more or less for shipping.
https://pepetools.com/products/engraving-block-6
https://www.gesswein.com/p-12931-6-...a_caa8dIfwvk8pLdtl2-X1eE_Qwjbbs8aAtboEALw_wcB