A New Touch for iPhone - Walt Mossberg - Personal Technology - AllThingsD

Walt Mossberg reviews the iPhone 5s

"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."

A New Touch for iPhone - Walt Mossberg - Personal Technology - AllThingsD