6.1". I once owned a 7 Plus (it was for a good deal at the time) and I hated it. The phone itself was decent (apart from the overheating and big white bezels) but it was far too big for my back pockets, always felt like it was going to fall out, and was too big for my hands personally. 6.1" seems to be the perfect size for me, big enough screen, small enough body for my pockets.