I have been using my 13" MBP for a couple of years but am looking to upgrade so that I can give it to my daughter, who needs a laptop. I notice that the 15" retina is the same weight as the regular 13" MBP. I travel a lot, I don't work on the plane etc, just when I arrive. I wouldn't mind the extra screen real estate that the 15 offers but was wondering if a 15 rMBP is a genuinely portable computer. Could anyone give me their opinion? Thanks!!