Well, I agree with Irock on the tumbled finish takes away from being a more valuable cabochon. I hear many people ask about cabbing machines and tumblers so they can make a million cabochons, etc. BUT, the polished backs and soft edges are done by many of us who make cabochons, by hand, from start to finish. The polished back can be hidden in a setting but still shows you took the time to do the full job on making a premium cabochon. As for "Soft Edges"; I set many of my cabochons in sterling silver settings. The soft (rounded) edges allow you to smooth the silver to the cabochon and looks quite beautiful (to me). IMO
There is a place for tumbled finished cabochons and I do it myself on some stones. When you are in the trenches fighting to sell cabochons for under $25 you cannot spend 2 or 3 hours making a custom shaped cabochon with a flawless finish by hand. I shoot for $50 and up cabs but many times the stone cannot justify the price, even if it was hand made and hand polished from start to finish. Quality, beauty and type of stone will set the price. Sadly, a very small portion of the market will focus on the hand made cabochon which has not been treated in any way. I thank each and every one of them.