To me the "value" in the machines is how they look and operate. I don't mean strictly whether or not all the decals are intact. I mean how the machine looks overall...the lines, how all the components look together, and the decorative touches last. To me, anyhow. What fascinates me is how they operate, and how easy they are to work on. Just the fact that some of them have been sewing for well over 100 years is incredible. The history behind them is worth more than the object itself.
That's my opinion of the value of them.