Panavise sells some nice stuff, but I don't think I'd like the one RS sells.
A board vise is one of those things that you keep putting off buying, and then once you buy one, you wonder how you ever made it without one. You can build one using new parts for $100, or if you watch eBay, you can get used vises and parts.
I built my own, using the following components:
05 - Base
308 - 5# base weight
315 - PCB vise. Comes with 12 inch bar, holds PCBs up to 10 inches long
318-22 - 22 inch extension bar, allows to hold up to 20 inch long PCB
With the 22 inch bar, I can fit a WPC power driver board, or sys11 MPU.