This is all just my opinion, so take it for what it is worth. I would say that around 70% of all 27" iMac displays have some level of yellow tint or gray banding issue. Now before you get upset and call BS, let me explain. #1) I have owned 4 mid 2010 27" iMacs #2) Living in the heart of Los Angeles means that I have access to many Apple Stores, and other Apple retail outlets. Because of this, I have been able to personally view about 10-12 other 27" (and even some 21.5") iMacs over the last month. #3) Out of the 15 (or so) iMacs I have viewed, only 3 of them I considered to be near perfect. #4) Out of the 15 (or so) only one has been perfect IMO. There was no visible yellow tint, or gray banding. (my 2nd replacement, or 3rd iMac that had a cluster of dead pixels) Dead Freaking Pixels!!!! still pisses me off. #5) Out of the 15 (or so) iMacs I have viewed, only 3 of them I considered to be pretty bad. #6) The rest of them had slight issues, and I would guess that the average user would not notice the problems (without being shown where they are). On a side note: Those of use who do photo editing, or graphic design are more concerned with a consistent and uniform display than most other users. So, you can see where I came with my guess of 70% (with issues). If it is that high, why not have 70% of the people return their iMacs? I think it has to do with the level of, or how bad the issue is. It also has to do with how easily you notice these issues. My first BTO 27" iMac was pretty bad. The worst one of the all of them. It was easy to tell that it had a significant yellowing tinge on the bottom half of the screen. The gray banding was just as bad, or worse. The problem for me is, once I identified the problem on the first iMac, (which was pretty bad) it became easier for me to see the issue(s) on other iMacs. Even ones that were not that bad. Maybe some of them would have even been acceptable to me, if I did not have the really bad one initially. What I am saying is that I am (somewhat) programmed to pick out these issues. That actually sucks for me. (However, again consider that the one of the primary uses of this machine was for Photoshop and LR3). My advise for anyone who owns, or is thinking of getting a new iMac. Do not look at, or perform the tests to check for the yellow tint, or gray banding. If it is not detectable in your every day use, then do not worry about it and enjoy it. Be a happy iMac owner. For those of us who have a reason to actually care about the quality of the display (for the reasons stated above) or who have been unlucky and received bad displays, please do not label us as trolls, or belittle us. For those that are happy with their iMacs, I am happy for you. You have (at least) a good one, and maybe even a perfect one. It does not really matter. You are happy with it and it is a great machine. It is just too bad that these issues really do exist, and not everyone gets the chance to be happy with their new iMac. If you think that people post their bad experiences because they want to make the happy iMac users unhappy, you are wrong. We are just pissed off that we are not (yet) one of the happy ones.