Just got mine hooked up and I'm having an issue with resolution.
Under no circumstances do I want the player performing upscaling (the upscaler in my 940D is at least as good and I've seen issues with players trying to upconvert and then the TV trying to do it as well). So, I set the video output to "Original Resolution". When I play a BluRay disc, the resolution information (what you see in the status bar for the TV) will show 1080/24P (as it should). Picture quality looks excellent.
Exiting the movie to return to the player's main screen switches the resolution back to 4K (3840x2160p) which isn't necessarily a problem at the menu screen.
When I launch NetFlix, and play something "old" (like a 90's TV series), the resolution remains at 4K and the Wide Mode setting kicks in to enlarge the video to fill the screen. This is absolutely not what I want, and makes it seem that the Original Resolution setting is not actually working correctly.
I'm also having an issue with the audio. I've set the HDMI Audio output for HDMI 2 since my older AVR doesn't support 4K / HDMI2 inputs. HDMI 1 is connected directly to the TV and HDMI 2 is connected to HDMI Input 2 on the AVR. When I play anything from the x800, my AVR auto-switches to the "TV" input which is a TOSLINK cable from the TV. According to the settings menu in the x800, choosing HDMI2 output for audio should eliminate the audio signal from HDMI1. Yet, audio is clearly passing along HDMI1 -> TV -> AVR (via TOSLINK). As a result, my AVR detects audio input on the TOSLINK and skips the audio in on HDMI Input 2 and I lose the audio quality (which is the whole purpose of having the second HDMI out in use in the first place).
I've also noticed a little "quirk"... If you launch Netflix and then try to open the tray (at least with the front panel button), you can't. You have to exit the application before the player will allow you to open the tray. Seems dumb to me.