What's cool about Apple's iPhone 5S is a little thing called the Apple A7. Actually, Apple's 64-bit processor is a big thing in a small package, just as an iPhone 5S would be under the tree. Archrival Samsung and others are working on their versions, but so far, Apple is the only company offering a phone with this kind of power, which speeds everything up exponentially and increases its upper RAM limit. The 5S also has a vastly improved camera and automatic security thanks to a home key that doubles as a fingerprint reader. It's probably not worth upgrading from the iPhone 5, but anyone with a model prior to that will welcome the larger screen, faster performance and future-proof design. And like all iPhones, it's available for AT&T, Sprint, T-Mobile and Verizon.