I think buying a used vise is like buying a used gun...
That's true in many ways, I think, including that it is very hard to find an affordable new gun or vise that compares to the quality and craftsmanship of the older ones. Also that one has to take more time in finding a used gun/vise that has been cared for and that does not have serious issues lurking beneath the surface. But when one does find a good old gun/vise, it can be a joy to use.
It's probably a matter of perspective, but I would take my 1892 Henry Atkin boxlock over a modern, machine made, laser engraved shotgun any day. Same for my 1971 AyA 4/53. And I would take my Parker vise (c. 1940s) over a new one as well. The baseline expectation of craftsmanship does not compare. Consider, for example, the retainer on my two vises:
Not only does the Parker have it's name cast into the ring, but the slotted screw seems to be indexed to be vertical when fully seated. Could be accidental, but even the handle is vertical when the vise is fully closed. [Notice, there is a tension screw that allows the handle to be kept at a middle position if desired.]
As for function, although my Parker was actually in pretty bad shape in some respects when I found it, there is essentially no 'play' in the screw and the action is smooth as glass. And the swivel base slides smoothly and locks up tight. My view is that the pride one takes in craftsmanship will be apparent and similar in both the aesthetic and functional aspects of a product.
From a purely practical standpoint, Wilton is essentially the last maker of domestic vises (for US users), and, as of 2019, even the Tradesman is being built in Taiwan. If you want a new USA made Wilton, the starting price is just over $1000 for a C1. As Ted said, you can easily spend 3-4k on a new Wilton.
Here's my tradesman before and after disassembly, clean up, lube and paint. The mechanical aspects of the vise were in great shape except I am going to have to straighten the swivel screw handles and replace a stripped screw in the retainer ring. I think it's going to be a good user
[For the record, I paid $125 (plus $120 shipping!) for my Parker (Facebook marketplace) and $140 for the Wilton (local auction). Both were good deals in my view, especially since I live in a vise-deplete region of the country. For those living in the Northeast or Midwest, good quality vises can be had for much less.]