— The 5S and the 5C are compatible with more 4G LTE frequency bands — up to 13, instead of a maximum five before. That means the phone is more likely to work with higher speeds wherever you go. However, there are more than 40 cellular bands worldwide, the bulk for LTE, so a version bought in one country might not work for high speeds everywhere around the world. If that happens, you'll need to use the slower 3G and GSM networks.
— Both the 5C and the 5S come with iOS 7, which offers a new look to icons along with new features such as a Control Center for easy access to frequently used settings and apps. Older phones can be upgraded to iOS 7 for free, starting Wednesday, although Apple says some features won't work with all models.
— The 5S comes in a choice of silver, gold or gray, while the 5C is available in green, blue, yellow, pink or white. On the 5C, the background wallpaper on the screen matches the color chosen. If sunny yellow for the yellow model gets annoying, you can change it to Apple's standard wallpaper, or any photo of your choosing. Or spend $100 more for the 5S and the normal wallpaper that comes with it.
Anick Jesdanun, deputy technology editor for The Associated Press, can be reached at email@example.com.