I just purchased a M3/14, and part of me kept agonizing over the idea that maybe I should have gotten a 16.
Better performance, better battery life, bigger screen.
But I had an epiphany today as I did some work on the train home.
The 16 is better for folks who move around, but do most of their work on a table. If you don't do much work on the train, the plane, the automobile or in your lap, the 16 is probably the better choice. It's only a pound or so bigger, so it's not that much harder to carry around.
But, as I sat on the train with just enough space to work with the 14, I realized that I would have been out of luck with the 16. I sit on the couch a lot, I work on the train, when I go on trips. For me the 14 is usable in more places where I do work.
Just wanted to share my thoughts.