I have the 13" Touchbar. It's a a nice laptop beyond any doubt. However, I'm about to turn 40 and my eyes aren't the best anymore from all the computer work over the last 25 years. I believe a 15" monitor would be fantastic. However, I work as a teacher and I have to carry my laptop around all day. How's the portability of the 15"? On paper, 1.8kg isn't very heavy and not much more than my old 13" rMBP that carried every day for years - but how is it in real life? How about the dimensions? Anyone with a 15" carrying it all day?