Just wanted to come and say.... I have had my MBP-R since February 2013
For about 3 months I had no image retention/ghosting issues. Then it started and got progressively worse.
I did the grid test and it retained the image for about 2.5 mins. I ran the terminal command and sure enough I had an LG.
I made an Appointment with the genius bar. They took me in earlier than my appointment (YAY!!!!), and ran their own test. Basically the same grid test I did online. They leave the grid on the screen for 4 mins, then make the screen all black for 60 seconds. Then the screen goes gray again and they get a pass/fail button. If they can still see the grid after 60 seconds it "Fails"
Let me state.... I am a major Apple "Fan" and always praise them and have bought every model iPhone they have made except version 1, and every iPad too... as well as 4 Macbook Pro's and an Air and a Mini in the past 3 years. I love Apple.... but I have issue with this test because:
1. Setting the screen to full black is not really "Reality" of how a normal user would use the computer. If I go from Facebook to Photoshop.... I do not want to see the "FB" icon shining through somebodies forehead... and I dont want to make my screen black for 1 minute to prevent that from happening.
2. Once the "All black" screen is done it goes to a shade of gray that is too light which disguises the effect of the ghosting. (You cant see the ghosting at all if the screen is all white because all white is basically cranking up the brightness on every pixel, so lighter colors obviously mask the issues more then a true neutral 50/50 gray)
3. 60 seconds is an eternity.... If I am editing pictures, waiting even more than 3-5 seconds is annoying... it should disappear instantly. Especially if I am editing images with the client next to me watching.... My retention went for 2-3 mins before fading.... but I can totally understand a person being upset if their retention went anywhere from 5 seconds to 59 seconds and being told "its within spec". As a photographer that is not Acceptable....especially for a Machine of this price... and even more so because previous highend screens do not have this issue... nor do other Retina devices such as iPad or iPhone.
Ultimately my screen got replaced and I was only at the Genius bar for 10 minutes for the whole process. They fixed it on site and it was ready for pick up the next day less than 24 hours later. I checked the new screen, and it is a Samsung. They did a very good job and were very friendly. A++++
BTW they replace the entire Top Lid. They do not take it apart and put new screen in.
For Color Sensitive people. I turned it on in the store just to make sure it "Worked". I could tell right away that I had gotten a Samsung replacement because the screen color was a bit "Warm"... (the LG screens tend to be "Cool" out of the box.
Once I got it home I confirmed that it was an Samsung using the terminal command. I calibrated the screen and the "Warm" tone has gone and it is perfectly neutral. I actually think this screen looks a bit better over all.
Hope this helps someone else.