Bought the 55C9 a couple of weeks ago - here in Norway.
During night scenes, I find the TV is barely watchable - I am playing 1080p movies via USB hard disk (also tried playing from laptop (VLC player) via HDMI cable.)
It seems too dark and I have to turn off all the lights to compensate for this. Vivid is the only mode, where I can see something in the movie.
No problem when the scene is not completely dark at all. No other complains for the TV. Upgraded from Panasonic ST60 plasma - so black levels and natural looking picture is what I was looking for and this TV does not disappoint.
(I have tried to play around with the isf mode and increasing the brightness does not help.) All the fancy features like superresolution etc. are turned off)
Errrr....don't touch brightness. Brightness adjusts black levels. Set it to accurate one and keep it there. Raise OLED light. I have it at 22 for dark room. Plenty bright.