It really depends on what you want to get the rifle chambered in. If you go with non-magnum cartridges I'd go with the FWT. If you go with a Magnum I'd probably pick the sporter. If you get a FWT rifle in a Magnum caliber you are buying is a sporter contour 24" barrel in a the FWT stock. The slim profile of the barrel and the trim stock is what makes a FWT IMO, I don't mind the looks of the FWT stock with a sporter contour barrel but it just isn't quiet a FWT.
As far as production leaving SC, I doubt it happens anytime soon. Plus if it does I'm sure the M70 is here to stay as I think sales have been going pretty well for them since they came back. They gave up trying to compete for the low end of the market and have placed themselves solidly in the middle, without making a whole lot of compromises to their product. The whole reason that they went to SC was to avoid the Unions that pushed them to bankruptcy.
Of course with the current political climate one never really knows what will happen next.