OnePlus 3 with custom ROM Paranoid Android 7.3.1, best smartphone display I've ever used. Can be made totally unusable by upgrading to latest OnePlus OS. Even the latest Paranoid ROM is unusable for me. Plus if I set the brightness too low, there's 240 Hz PWM that makes the screen unusable for me, too. So there's 2 factors: PWM, and OS pixel control. I think PWM doesn't need an explanation: some can use it, some can't. About the pixels, I'm not 100% sure. Other than that, perhaps, Paranoid Android 7.3.1 leaves the default colors untouched while, maybe, all other ROMs decide to change the default color profile. They call it "default", but it seems altered. Slightly different white for example. I think the algorithm responsible for color profiles does temporal dithering or something similar, resulting in eye strain. And this was a lucky find. Maybe it is the reason most Android smartphones are unusable for us. This can turn a perfect display into something unusable.