The larger 55" models seem to have an issue with flashlighting from the corners. My 40B6000 does not, but I think it has more to do with its size. The XBRs I really have not seen but have heard good things. Let your eyes decide, and really try to spend some time in front of these 120hz sets. The one I have, the B6000, was very hard to watch, it actually made me sea sick. My 60hz sets do not have this effect on me, nor does my Sammy 58B560 plasma.
Consider the Samsung 52B750 --- being recognized as the king of the hill LCD for now by many or wait a few months for the Sony 65" W5100 for HT Size. (provided they haven't cancelled it with recent cutbacks announced)
I got a samsung 7100 from bestbuy. Bright screen but it is so glossy. We have windows and the glare can get bad during the day. I was at a sony style store and saw the xbr9, it looks great. If I had to do it over again I would go xbr9.