Just got my Space Grey 256GB from Apple. The color shift is HILARIOUSLY bad with True Tone on. It shifts on a white screen even if I tilt the phone the teeeeeniest amount. It's pretty ridiculous, actually. Goes yellow or blue depending on which direction you shift.
To be honest, even my LG C7 65" OLED TV has yellow/blue color shift depending on seating position. Nobody seems to care much there (I DO!), so we'll see how much people care here.
Also, seems OLED still can't do whites. The whites on my iPhone 7 Plus are blistering white, and on the iPhone X they're kinda grainy, and ...of course... the color shift.