I personally enjoy having chips that have some sort of error associated with them. I think there is a market out there for error type chips. Of course a lot depends on the type of error too and the casino in which it is from...

I don't think slight printer color overruns are too interesting but a chip with the same inlay on both sides always seems to garner a lot more value than a non-error version.

Obviously that Dunes chip is not one that has a duplicate inlay on both sides and that appears to be a printer error. I do feel it is more than just a slight color overrun though.

I too do not feel is loses its value because of the mistake. I feel that if you have the right chip desirablity combined with an error (such as in the example of the Hard Rock errors), watch-out, the price explodes!