Some photos. Left is iPad Air 2, right iPad Pro 9.7. On the first photo you can see even off that the screen on the left is bluer than the one of the right. On the second photo, there is a visible bluer/whiter cast to the pic on the left (honestly here I prefer the iPad Pro, the blacks are blacker)
Here its quite visible that the Air 2 has a "whiter" or bluer cast that the Pro. Honestly if I was to look at the photos I would totally say that the Air 2 is the more "correct" color (certainly it makes brushed metal objects look better), however in person the difference isn't quite as pronounced. The camera is boosting the difference (a similar photo of the settings screen with both devices on lowest brightness in person is barely visible, however a photo of it makes both quite visible)

Between the two home screens, there isn't a whole lot of difference, I think on the Pro the icons with white look better. On the pic of the girl, the background on the Air 2 seems whiter and the skin tone is a bit more natural. However in terms of the white matching the white paper, at least in person the Pro's screen matches it better.

I'm not going to try swapping for a different screen as there don't appear to be any dead pixels and the tone is even & no obvious backlight bleed (which I had on my first Air 2, which had a warmer screen than this Air 2). The only reason I might exchange is because I'm in two minds about whether going for the 12.9" Pro would be the better option (for general moving around the house, cooking and stuff the 9.7" is a better fit, for reading comics/mags the larger screen would be appreciated)
Turning on the TrueTone on the Pro, and then off again makes the screen seem incredibly blue in comparison to itself. I tried to capture the difference (on the settings screen), but flipping between the two photos I was hard pushed to see the difference despite it being quite marked in real life.