As for the screen, I think "gimped" is not doing it justice. I regularly use both, the Air's is a very nice screen in its own right and while there is a difference, it feels more like a relatively small increment on something already very solid, at least to me (I don't do any pro photo/video work). Same for the other differences, the Air's speakers are already pretty good, connectivity is fine (for me), I like not having a fan, it's way powerful enough for what I do.
The Air is noticeably lighter and much easier to throw in a bag without thinking about managing weight. The Pro is a fine weight for commuting, but for traveling longer distances, the weight definitely makes a difference. To the point where I'm seriously considering setting up a work partition on my personal machine so I don't need to lug the pro around on an upcoming trip.