It's interesting, I went back to the CD-i thread with Zelda's Adventure and I estimated over $100 based on an actual previous Ebay sale while you thought the estimate of $300-$500 was more accurate since the retail version always sells for over $300 despite the fact that you had nothing to back that up. You then only ended up getting $200 for this allegedly rarer version. So, what happened? Is it possible you were just flat out wrong about the value and were using the same fuzzy logic that results in estimates of $27K for a NWC Gold when the highest previous sale was $17K?
On the Vectrex imager, you were positive yours would sell for as much or more than the one that sold the week before on Ebay. As we both know, it clearly didn't. So again, do you really have a solid handle on pricing when your two major recent public sales have fallen well below your estimates?