OP, I am about to be in the exact same situation as you - I own a 14" MBP and have a 15" MBA on order.
I went into my local Apple Store to try to see the 15" Air just out of curiosity, because it's a product I've thought Apple should make for a really long time and I was excited to see it come to fruition. I loooooove the mini-LED and ProMotion on my MBP, so I didn't anticipate putting any serious thought into switching, but when I saw it in person... Wow! The screen looks considerably larger than the 14"'s, and it's beautiful. Enough of a significant difference in screen real estate to make me consider one.
It's funny, when you look at a DisplayWars comparison of the 14" MBP vs. 15" MBA they really don't look significantly different. And "16% larger area" doesn't sound like all *that* much. But again, the difference in person was noticeably discernible. Keep us posted with what your decision ultimately ends up being.
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