The Bottom Line
The iPhone 5s runs iOS 7, of course, Apple's super-fast 64-bit mobile operating system, plus 64-bit versions of all apps, libraries and drivers. Meanwhile, the S5 runs the mature and refined Android 4.4.2 Kit Kat plus Samsung's excellent TouchWiz UI overlay. Both offer trillions of apps, amazing power efficiency and super-long battery life. The iPhone 5s has been available since September starting at around $200 with a contract from AT&T, Sprint, T-Mobile or Verizon. The Galaxy S5 will begin shipping in April for AT&T and Sprint networks; pricing has not been disclosed.