I spent a few minutes at an Apple Store holding an iPad Pro with tandem OLED, and I couldn't perceive any difference with the iPad Air right beside it.
(The even more expensive nano texture option was worse. It simply felt blurry.)
One needs to use them in their personal lighting situations, not in a store.
I have both the current and prior iPad Pro version. IPS+Mini LED and the Tandem OLED. The IPS version was already great. The Tandem OLED is generally better, but often not by that much. It's also a bit brighter. Both are quite a bit better than the normal iPad displays.
I've seen the nano texture version of the Tandem OLED. Reflections are much less, but in brighter surroundings, the image is not that dark. But again, it all depends on the personal lighting situations.
That would be a worse case scenario. The Apple stores are incredibly brightly lit, and you’ll be hard pressed to notice wining isn’t differences between any display type in such an environment.
These displays and their content are intended to impress in media viewing situations in which you’ll light control accordingly. They’ll still look good outside of that, but they offer so much more when you want to dim the lights and kick back with one on the couch with a movie or whatever.
Now if I could only get one in a size I cared about, I could be rid of LCD permanently. Alas, I doubt I’ll see this in a size suitable for what I want it for in less than 5 years or more.
(The even more expensive nano texture option was worse. It simply felt blurry.)