What are the main differences between an iPhone 5S and an iPhone 5C? I am not sure which one to buy. They look similar.

The iPhone 5s is slightly different from the iPhone 5c. But there are 5 main differences:

1. Speed - The iPhone 5S has a faster processor than the 5C. The 5S sports an Apple A7 processor, while the heart of the 5C is a 1Ghz Apple A6. The A7 is a newer, more powerful model than the A6, particularly because it's a 64-bit chip (the first in a smartphone, according to Apple).

2. Motion Co-Processor - The iPhone 5S is the first iPhone to include a motion co-processor. This is a chip that interacts with the iPhone's physical sensors--the accelerometer, compass, and gyroscope--to provide new feedback and options to apps.

3. Fingerprint Scanner One of the iPhone 5S's headline features is the Touch ID fingerprint scanner it has built into its Home button.

4. Camera - When taken just on the specs, the cameras in the iPhone 5S and 5C don't look very different: they both max out at 8 megapixel still images and 1080p HD video.

5. Price - iPhone 5C is cheaper than iPhone 5S.