Which model does 120 Hz better? I've heard that one guesses and makes the next image while the other one does actual 120 Hz. These 2 TVs are always hard to compare, but the 120 Hz can make a big difference.
I have read where the Sammy's still have a motion blur issue, check the hdguru review for an example. I have seen the Sony have the motion blur problem, but mainly in vivid mode,,
They are both outstanding panels - go study them until you can decide what pleases you and then pony up the cash. If you can't fully decide flip a coin and buy with return rights.
If you still can't decide may we assume your single since a married person would have all kinds of recommendations whether you want it or not from a wife even if she's not footing the bill.
I did hours upon hours of research on what TV I should get. I ended up with the 52" XBR5 and I'm more than happy with the TV. Either one you cannot go wrong. To be honest, I think it should be the 81F vs. the XBR5.. (basically both companies top of the line TV's)