I just wanted to share my recent experience. I sent my set back (Nov. 2013 build) due to banding and not seeing the clearest picture on my Verizon FIOS set top box. Blu ray was fine, but I felt that the HD content on cable should have been better. After calling Sony support and giving them my serial number, they put me on hold. My understanding is that they were able to run tests on my unit to see if it was defective. I only assume this because they offered to replace my unit. I doubt they would do this for every customer complaining about banding issues.
They offered to send over a factory re-certified unit. I was hesitant to accept this due to the fact that my unit was new. They informed me that these units do not have any damage, but were returned for similar reasons to mine. They are then sent through an extensive series of hand testing. All of these issues that we discuss on this forum is making it's way back to Sony (not directly, but you know what I mean), so they look out for them in the hand testing. They offered a two year warranty instead of the standard one year. To me, that shows that they have more confidence in the re-certified units than in the new ones.
I have had the replacement for about a week now. I have not seen any banding issues and the picture seems to be much clearer than my last unit. The only issue that I still see is with sports tickers (NFL Network, ESPN). When the text scrolls, it seems to studder. This seems to be a motionflow issue, that not many can figure out. It is an inconsistent and tolerable issue though. Overall, I am very satisfied.