Previously owned: Pioneer Kuro (deservedly legendary as far ahead of it's time) & then Panasonic Plasma (very good).
Current Set-up: Run all through Integra Receiver then out to Samsung OCB
Up and running 3 days
Tweaks: cut out most all the extra processing but no changes to detailed settings
One Major Change that really improved picture
, especially upscaling: use "Natural" rather than "Standard" (For me "Standard" had that somewhat pasty, muddled image some have noted - but not as bad as the often noted camera picture submitted on here - camera pictures are unreliable, I've tried - so will not be posting pictures)
I'm anxious to see other peoples ideas on changing the detailed settings; but I'm totally satisfied as is.
Conclusion on Samsung Q90R 65": Excellent
Notably Very Good To Exceptional Features:
Picture Quality of 4K Content (of course)
Detail in black areas
Picture Quality of most all other content (with all subjective elements that go into such an opinion)
Wide angle view
Upscaling (yes, and I'm on ATT/U-verse/DTV)
Not Impressed With:
Remote (it's okay, but so far I still need other remotes for efficient operation)
ARC audio not working through OCB for Prime Video so audio only through TV Speakers for Prime Video (Cable & Blu-ray audio runs well through Integra/External Speakers) - and many thanks to bjorktribe
for his ideas on how to solve ARC issue but still a problem.
I am sorry a few are dissatisfied with picture quality; but many on here are thrilled like me! I suspect many of the issues are not from real owners; but are just repeating what a few have suggested or even speculated on. And many people repeating the truism that garbage in = garbage out (bad source content) makes it appear that there are many more disgruntled people than there actually are. I've also had way too much of the oft repeated theoretical opinions and scenarios about how bad content can not be corrected and how 4K TV's will look worse on ALL non-4K content. That is simply not true on this TV for most sources for most people that have posted here so far. Obviously true for a a few sources and a few TV's.