I have been going back and forth between the two, and "adaptive" gives me too much lightened areas in "black" areas. Almost an LED type wash. The TV I have is the LG 55EF9500 (the first flat OLED LG offered. Bought one month before the Hopper 3 was released) so it only has HDR 10. (and not a very good one at that. It turns red into shimmering orange). Trust me, I know about calibration and I have as true a setting as possible using the various set-up discs(memorized as ISF Expert #1). But I believe the old boy has aged and gotten dimmer so that a little "fake help" gives a more pleasing presentation with casual viewing. That is why my question is so important. If it does no harm when a true HDR10 signal is offered, I'd just as soon leave it on.