FWIW, 10 days ago I bought a Mac Book Pro 13.3 inch (2.6 GHz Intel Core i5, Retina Display, 256GB SSD, 8GB DDR3 RAM & Integrated Intel Graphics) ... I was planning on using it for editing photos while I'm traveling, but I find myself using it more than my iMac ... currently I'm running lightroom 5.2 & PS CS6 (with a few plugins) ... it feels a lot lighter and thinner than my earlier MBP (core i7, mid 2012 model) and works very well and lot does a very good job of running lightroom 5.2 & CS6 simultaneously ... and the Retina display is awesome as always.
I have the 13.3" MBP retina and the new 11" MBA. Buy both if you can afford it. Despite what the Tarzans say about weight, every oz or g saved makes a difference for me when I travel, especially as I go everywhere in the world with only cabin baggage. Both are awesome.
5D IV, 5DS R, 7D II, EOS-M, Powershot G3 X, 400mm DO II, 300/2.8 II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 70-200/4 IS, EF 24-105, 15-85, 100-400 II, Sigma 10-20, Sigma 150-600mm C, EOS-M5 15-45, f/2 22, 11-22, Samyang 8mm f/2.8 fisheye