Both had image retention problems. The first one actually came out of the box with IR that never faded, while the second one was the ordinary kind as others have reported. Neither was $2500+ worthy, or anywhere close.
my lg screen on my RMBP has started showing retention issues. Honestly it hasn't affected its use at all though. I use it for graphic work, general browsing and occasional guild wars 2.
I may give the rMBP retina one last shot after several returns. Just wanted to check in with the new owners for the month of September, which display have you been receiving? Maybe Apple is now only shipping out Samsung displays due to the numerous returns of rMBP with LG displays.