Hi Bill, like many people I am still waiting for my iMac to be delivered. The reason i am so concerned and aware of the IR issue is the 426+ page MBPr thread
here As soon as mine arrives, I will be testing, posting, and very involved.
Apple has been deleting posts in the thread, most worrying resetting the stats, and basically trying to hide their problem from the world.
IR is only a problem with LG displays (within the scope of MBPr's) as far as we can see on that thread. There are thousands of people who have given their time to help others, and Apple is now only using Samsung LCDs to repair MBPr's with IR. So even Apple quietly acknowledges the problem is with the LG LCDs.
I have tested iMacs and Thunderbolt displays at stores and have not found any IR. So if you have having some IR, you should take it right back to Apple. I don't think this situation is the same as the MBPr one... as the LCDs are both from LG, but different technology.
Apple should have better QC as they outsource so many components...its Jaguar back in the 80s, beautiful car, amazing design, but frankenstiened together and a QC nightmare.
http://en.wikipedia.org/wiki/LG_Corp They were Goldstar and changed, their name. Remember Goldstar?