Apple brings out a new top-of-the-line iPhone model every year, but a redesign only every other year. In the intervening cycles, the company tends to keep the phone's exterior the same, but change the innards and the software. This is one of those in-between years, but the new iPhone 5S has a potentially game-changing hardware feature and a radically new operating system.

The iPhone 5S is the first digital device I've seen with a simple, reliable fingerprint reader—one you can confidently use, without a thought, to unlock the device instead of typing in a passcode. You can even use this fingerprint reader, called Touch ID, to authorize purchases from Apple's App, iTunes and e-book stores.

It sounds like a gimmick, but it's a real advance, the biggest step ever in biometric authentication for everyday devices. After using Touch ID, I found it annoying to go back to typing in passcodes on my older iPhone.

The new iPhone 5S, which starts at $199 with a two-year contract and goes on sale for all major carriers on Friday, has a beefier processor that Apple says can double its performance. And it has a better camera.

Then there's the new operating system on this phone, called iOS 7. Its new look, new user interface and new functions represent the biggest overhaul to the iPhone's core software since the original model launched in 2007. Nearly everything has been improved, including multi-tasking, notifications, access to common controls, email, Web browsing and Siri. Like any big change, it's a shock at first, but I have come to like it and consider it a step forward, despite a few issues.