I assume the same can be said for active 3D on a 4k display. Except active is still referenced to crosstalk. I think that was eliminated years ago and those with crosstalk problems these days are pretty cheap displays hardly comparable to expensive OLED's. It's like paring a bicycle with a Ferrari at the drag strip. My active display has no crosstalk at all. None. "Some active 3D TVs deal with it better than others, but passive 3D TVs are virtually crosstalk-free." I guess my two year old JS8500 panel deals with it better yet it's no Ferrari. I think using the crosstalk downplay these days is fake news to further enhance the OLED pump, plagued with other serious problems manufactures do not acknowledge nor warranty.
"When a 4K resolution TV uses passive 3D, however, the extra pixels play a much more obvious role. You still lose half the vertical resolution, but since there are so many more pixels, you can afford to lose it." This fact says it all. Can you afford to see alternating lines of vertical black pixels up close or on large screens?
Active delivers full resolution to each eye. Passive delivers half resolution to each eye. It's a step up from 1080p displays for passive because there's so many more pixels to help enhance the halved resolution with 4k but it's still halved.
I don't think one is more superior than the other except when it comes to resolution, my personal largest factor.
Active downplays of note are:
Crosstalk would be a huge factor if it actually existed for me.
Motion would be another but luckily interpolation settings eliminate it for me and I prefer SOE even if motion didn't benefit from using it. I'd be curious to know if OLED passive displays news tickers judder or not? You know, the headlines or tickertapes scrolling the bottom of the screen are either smooth as butter or skipping like a machine gun at times.
Comfort from flickering in the glasses. I guess I'm not sensitive. I've never experienced it much less got a headache because if it. Not to say somebody else might not.
Batteries. They only last about 20 titles and cost me about a quarter to replace. Snapping new ones in and out of the glasses might be cumbersome for somebody? USB charging glasses might also be inconvenient next to the charging cell phones too.
I agree with the OP, Active or Passive, 3D upscale on a 4k display looks much better than the same title on a 1080p display.