iPad Mini Retina v iPad Air displays
I'm not oversensitive on display quality. If I like it and I can't see the pixels I'm happy. To be frank, I was happy with last year's iPad Mini although even I can notice the difference with the latest device in my hands.
Fortunately, it is encouraging that not everyone is as subjective when it comes to comparing devices. One who really does know his displays is Norman Chan of Tested.com. He gets down to the pixels in this informative article and even explains how Apple might build a bigger, 4.9-in iPhone. Required reading for pixel peepers.