I'm getting tired of my Moto X's instability and horrid battery life, and considering a return to iPhone. The last one I owned was an iPhone 4, and I could eke out 2 solid days on a single charge on that thing. Which of the more current-gen iPhone models have comparable battery life? I'm considering side-grading to an iPhone 5c, but maybe waiting until after the next Apple announcement to see if they go down even more in price. I know the 5s has the fingerprint reader, but I'd only consider it if the battery life is significantly better. Would love a 6s for 3D touch, but I'm not willing to spend $750 for it (I am done with 16GB models). Thanks!