@OrangeMarlin, instead of being ignorant, just a quick search on the Apple support communities will show you that I'm not alone at this. Acutally, don't even look that far, jCurve above is reporting the same thing.
Anyway, I will say that Apple support was great and that they issued the refund promptly and without too many complications. I really liked that new iMac, it was almost the best desktop I've ever had, but in the end of the day, between the image retention issue, no bootcamp on 3tb and other annoyances, this is hardly a perfect machine.
As I said - will revisit iMacs when they figure those issues out.
@jCurve, Apple did say that they have heard of this issue, espically with the new Retina display Macbook Pros, and their view on it is that it's a "minor" issue that is easily resolved if you turn your screensaver on. I explained that a screensaver won't help when I use a program like Xcode or Word, where the same window is visible at all times, leaving a blue frame behind it when I close the program down. They had no answer, so had to give me the refund.