I have the late 2010 MBA and while it has served me very, very well for the past two years, it's starting to noticeably slow down, especially after upgrading to 'insert latest version of OSX.'
Safari lags when I quit. GIFs take forever to load. Apps crashing left and right. Random reboots. Shitty battery life.
Nothing too dramatic to the point of my having to buy a replacement, but it's starting to show its age.
When I checked out the 13" rMBP, it was very very nice. Felt good in my hands. Biggest drawback, though, was the weight.. Everything just feels so much heavier after my MBA and since I do all of my computing/browsing in bed, it's more apparent, unfortunately.
I could potentiallllly see myself getting a 13" rMBP, but only for the fact that it has pretty good battery life.
That being said, I do believe that the rMBA will be a wild hit as long as it's not prohibitively expensive and the battery life is decent. Too bad none of those will be true with the first gen.
I'll probably stick with my current MBA for another year or so.
Edit: Also, I wish they'd update the design of the Macbooks. Starting to look stale now. I had the older MBP back in college and I actually prefer the tactile feedback of the old version's keyboard to the current style's. Also looks 10X better, IMO. Never was a huge fan of the black keyboard.Edited by GreenFrog - 2/27/13 at 8:00pm