Only you can choose what you think is right for you.
As to what the TV makers want to sell, that's about to change again if I'm reading CES 2019 right with 8K HDTVs about ready to roll out.
I've seen HDR side by side and sometimes it's better, sometimes it's a wash. For me it's not a deal maker or breaker.
I am quiet confused about this because I read very different things on different forums, and well, new to HDR content and this TV as only one source, I cannot compare things to anything else. Some say, that the "right" color space to use for HDR content is bt.2020 because it is the more "realistic", some say the right one is DCI P3 because bt.2020 washes out the colors while DCI P3 brings them out.
Indeed it seems to me that P3 is more colorful, brighter, but I have no idea how the picture I am seeing SHOULD look like, or "intended" to look like so I do not know if P3 is too oversaturated, OR bt.2020 is too washed out.
For this TV, which one is the "correct" choice for realistic, proper image?
(The default option is DCI P3, by the way, but that could mean anything, seeing how the manufacturers want to sell the TV with "bright and vivid colors")