I was going to make this point myself, but instead I'll expand on your comment.
If you look purely at power usage, iOS uses way less power than the Galaxy (Pure Android is pretty neck to neck, but TouchWiz drains battery like nobody's business.) If you know how to
manage your phone properly, battery life is pretty good on iPhone too. Turn off Wi-fi and Bluetooth when you don't need it, don't keep the screen at max brightness if you can see it just fine at 60%, etc. Another good trick for iPhone 4 users on iOS7 is to turn off translucency and parallax, as it allows your CPU/GPU to go to lower clocks. Doesn't make much difference on newer devices though, as the minimum clock speed can achieve translucency and parallax no problem.
Even though the Galaxy has a much bigger battery, the difference isn't that great in actual use when all comes to all. On iPhone you can manually do pretty much all that power saving mode on the Galaxy does (turning on black and white mode on iPhone doesn't increase battery life. On an IPS display, it takes just as much juice to do colors as it does blacks and whites).