The iPhone 5C has the same processor, rear camera, and Retina Display as the iPhone 5. But Apple didn't just slap a series of colorful plastic cases on last year's phone. On the inside, the 5C is a unique device, with hardware upgrades and design elements from both the 5 and the new 5S.
On the outside, it's the iPhone 5C's choices of colorful polycarbonate case that really set the phone apart from the 5 and 5S. And thanks to this case, it's also slightly longer, wider, thicker, and a bit heavier than the other two iPhones.
But peel back the case, and the 5C reveals itself to be a unique device, which borrows traits from both the other phones.