I had a similar feeling to the OP for my first impression...I guess I was so excited Apple finally adopted OLED and was expecting such a monumental leap in screen quality that I was a little let down. Don't get me wrong, the display looks good but the differences are subtle compared to my plus during everyday use. I wouldn't call it a deal breaker but definitely expected a little more wow factor when turning it on for the first time.
Same feelings here. I keep turning True Tone on and off to see if I like it. It is aggressive to me, making the screen more yellow than I like.