I find this to be true as well. A ~13.5" machine packs easily and, is noticeably more useful to me than a 12". And 12" is just a little too small for my prefer

I find this to be true as well. A ~13.5" machine packs easily and, is noticeably more useful to me than a 12". And 12" is just a little too small for my preference, though not wholly unbearable. My 15" and larger machines have been much harder to travel with easily. For productivity, I have usually preferred the 15"+ machines. If that were the only consideration, then I wouldn't think twice. But they have been a pain to haul.