13", i7, 8 GB, 512 GB SSD?
I'm wondering if this is a logical purchase or just a "why not?" purchase. There is no way I am getting the new MB with the specs it has (and it's a 1st gen), and I'm supremely happy with my rMBP (mid-2013) that is fully decked out on specs. But a 12 hour MBA with full specs seems like a good purchase. Is there any reason not to go all the way on a light little tiger that will probably survive five or six years? Airplanes and meetings are delightful with a MBA.
My only reservation is the screen. I had an 11" MBA that I ended up selling because I didn't like the screen and battery life. But the 13" seems to compensate in some respects.. Even though the new MB has a Retina screen, I'm thinking it will be outdated within one year because of its sub-prime specs.
If your fully decked out Haswell rMBP is functional and performing well - why are you even thinking of buying another fully decked out machine? Why not use what you have, since what you have is fully decked out, it should have no problems cruising on for the next few years. Maybe take a look in once Skylake or whatever comes after that?