One thing I don't understand about the warm nature of True Tone on the iPhone X, is how different it is when compared to the iPad Pro 10.5. If the color is so accurate on my iPad Pro, why is the iPhone so much warmer in color with TT turned on? Sadly, I have it off full time (so far) on my iPhone, where I keep it on when using the iPad Pro.
I am a bit skeptical of many of the shots posted of the screens using Smartphones. Since there is so much AI and machine learning going on within phones, I don't trust color representation. While using an SLR still has it's flaws, I took some shots of a few screens using my SLR in RAW, Converted the shots to JPEG using Canon software on my Mac Pro.
All phones are at Max brightness with True Tone status listed in the image.
CAMERA - Canon EOS 7D
LENS - Canon EF 24-70mm f/2.8L
ISO 800
FOCAL LENGTH 24.0 mm (37.7 mm in 35mm)
APERTURE f/5
EXPOSURE TIME 0.002s (1/500)
Depending on what type of system you view these on, and your monitor / display calibration, the differences may not be that significant.
TT off, I couldn't be happier with the display, and think it compares well with the AMOLED screen in my standard Pixel 2.