FWIW I'll share my experience. Just received a retina 2 weeks ago with an LG...loved the screen but it did exhibit ghosting (week 43 or 44) and this forum made me completely paranoid that it was going to get worse...which I think it probably would have....but then again, even if it did, I'm pretty sure Apple would have replaced it once it became obvious that it was an issue. I don't think their stance has even been to screw the customer. They seem pretty accomodating and forgiving on issues such as these.
In any case, I was thinking about returning it but opted instead to go for a replacement, as it seems most (if not all) are being replaced with the Sammys. I went to the Apple store....NEVER expecting to fail the IR test, as it was still really slight, but somehow it failed. Then I received the email with that whole 666-7171 (?) part number and had my screen replaced....and indeed it was a Samsung. Couldn't notice much difference at first, other than that the viewing angle was slightly worse as there was more color shifting in the greys/some colors...and I HATE color shifting, but it's really not that bad. Anyhow the screen looks great (no yellow banding, no pixel probs), etc. And now I can rest easy that I don't have to worry about future problems.
One last point which I found interesting was that I was getting pretty iritated at the store before the screen test and asked how much longer I'd be waiting to which he grabbed a genius and asked him to get on the "NSP" ASAP. I was trying to figure out what that might stand for...."New Samsung Panel"????