I think the hardest thing for me, if goin to a 4S from a Nexus, will be the downgrade in screen size. I have gotten pretty comfortable with the large screens. Before my Nexus I had the 4.3" Galaxy SII. And before that, the Nexus-S, with the 4" screen, and I find that size to be actually perfect for a phone. This Galaxy Nexus at 4.6" is my limit for screen size. Hard to reach top of phone one handed.