Im returning my 8550. I really dont want the curved so I'm getting the Vizio M series since I dont really care for 4K and alls I want is the best dimming which seems to be the e/m series according to CNET.
I have my 8550, watched gravity -- turned the movie mode backlight to 8 and you will notice washing out on the bottom letterbox (for this movie in particular) in certain scenes, the blacks do indeed change (in a dimmed room). This, as I said earlier, did not happen on last year's f8000 because it had cinema black and only the 9000 series has cinema black.
I tried all settings, pumped up dynamic contrast, Smart LED to high, etc -- but the truth is the cinema black is a big part of it and if cnet says that the letterboxes are less washed out than the f8000 on the e/m series, I'm going with that TV (though I know a lot of you want the 4K).
Also its probably a bit more difficult to dim 4K due to more pixels.
Eh, seems amazon will take a 1 to 2 months to ship this tv. Man.
*I envy you that dont mind the curve. I think the curve will atleast be on the top 5 for dimming this year, probably #2
or 1. Cinema black would have made the 8550 perfect