The screen size is a sticking point for some folks, but the device doesn't "feel" big (my dad is a vocal critic of too-big phones, and he rather likes my N4) like some other phones of similar sizes. The battery life is absolutely an issue, but that's a software issue rather than a hardware one; I average about 36 hours on a charge on my N4, but that did take a bit of tweaking (turning off location reporting services that are on by default, primarily) to get there.
All that said, I feel that in terms of software, stock Android is so much better than iOS at this point that it's not even a contest; the "battery life" issue is part of the double-edged sword that is developer freedom - on the other edge is a system that lets developers do wonderful things. Apple is absolutely still top of the game in terms of hardware, but they're going to have to do a hard burn to catch up on software.