I've found they go for about the same as run-of-the-mill FNs on GB for the most part. Had a couple, including a Viscount with a trigger reminiscent of a Mosin-Nagant, and one of the nicer ones with the adjustable model. If I were in need of a Mauser, I'd consider them along with the others, based on condition, price, etc.
Some of the complete FN sporters and of course Brownings, have nicer stocks and such, but then every Mark X I've seen has a nice hinged floorplate, while FNs may have slide-off or crappy aluminum ones. My recently-acquired Husky FN has the slide-off, which I don't mind. It also had a crisp, but really heavy trigger, which now runs just under 4lbs with the help of a spring from a Wolffe 77/22 kit. The jury's still out on the beech stock.
