I do not have any experience with color depth or digital photography in any way or whatever, but the difference is obvious between MBP and MBA.
Use both for a while, if you don't see a difference good for you (or not, whatever).
Lots of people are getting all excited over the higher resolution but in the end it's sad if that's all your eyes can perceive.
Sure a higher resolution is nice but if that's all there is, with a step backwards concerning display quality, then if it's sad, like going from CDs to those pathetic MP3s. Yeah you can have more, but at what price?