Stan, I had a similar problem at BB. For weeks they've had the 55 running a 3D promo (in 2D) and a 46 running an animated feature in 2D, which looked great though I really wanted to see a feature film. The 55 was next to an EX700, which is not a fair fight.
A big concern I've had is reflections and that did not appear to be an issue, though you could see them against a very dark screen, but not a surprise as this is in a bright store. After researching and hand wringing for over a month, I took the plunge and ordered a 55. Unfortunately, they can't deliver and install everything until Nov. 1.
I'd been waiting to see the NX810 but my BB doesn't have it in yet. From everything I've read, it doesn't sound like there is a significant PQ difference between the two, just opticontrast vs. deep black panel and a few bells and whistles (I don't care if the Sony logo glows). I did see the LX900 and my untrained eye thought it compared well with everything in the Magnolia area, including the top end Sammy plasma. Again, similar bells and whistles differences with the HX800, from what I've read. If BB gets the 810 within a week or so and it just blows me away, I'll have time to make a switch. As it is, I'm comfortable with this choice.