You REALLY cannot judge a TV by what you see in the store because you have no idea what settings they are using and 99.9% of the time, they are incorrect for normal viewing. The reality is, those are likely the same 55" panel made by Samsung (Sony builds TVs using Samsung's panels) and Samsung does a better job integrating the panels into an actual TV. I have the 2012 55" LED edge lit Samsung and I am very happy with it.
Motion blur is a setting that can be adjusted or turned off on ALL LCDs today, and all of them do a pretty good job of it at the level you are looking at.