I have one of each but as I never buy a rifle as a speculation, I hadn't thought of it from that point of view. As a wild A$$ guess, I'd say the Savage because scarcity is often what drives value and there are probably enough 8x57's, beaters and otherwise, around to last forever. You can still buy milsup 8x57 ammo quite cheap. Also, I understand the 8x57 is still quite popular in europe. The Savage was surplanted quite a while ago by the .308.
I would say the quality was the same between them.