I see the difference! Just spent a good amount of time at the local BestBut playing with the the 13" pro and air side-by-side. Fonts on the air are a little smaller, but more crisp. Pictures and videos on the pro are a bit more colorful, but less defined. With my astigmatism, I have been leaning toward getting the pro (because fonts etc were a bit larger), but now I'm certainly in favor of the air precisely because of the detail.
Now my only remaining dilemma is 128 gb vs 256 gb ssd and 4 gb vs 8 gb memory.