Just purchased the 55" C9. It was delivered last Friday and I spent a lot of time trying to find the best user settings for my setup. The main source is Directv, but I did pick up a 4K player. The only disc I own at the moment is the Spears and Munsil UHD test disc. When viewing the demonstration material, I have to be honest, it doesn't look any better than any 1080 source. When choosing DV or HDR, it looks the same as the SDR choices.
I borrowed a 4K disc and it too looks underwhelming. The same holds true for the Home page APPs, netflix or Amazon Prime. The HDR logo appears on screen, but it doesn't look any better than HD.
Is there something that need to be implemented in any setting that will improve what I am seeing with HDR sources?
I had a Sony 55" A9G and even though there were some problems with it and it was returned, overall, I think the picture quality was a tad bit better.
Prior to either of these OLEDs I owned a Pioneer Elite Kuro. It was a real gem and I'm kicking myself for selling it.