The jump from the iPhone 5 to the iPhone 5S was nowhere near as significant as the leap to the iPhone 6 and 6 Plus - Apple’s handsets changed notably inside and out at that point, and their release should give you serious pause if you’re looking at buying an iPhone 5S right now. The iPhone 5S represented the pinnacle of that particular iPhone design for Apple, before it went thinner and more rounded with the iPhone 6; it was certainly very difficult to tell the 5S apart from its predecessor, the iPhone 5.But that same issue was apparent already in my iPhone sample within a week, so it looks like you’re going to quickly need to stuff your new iPhone 5S in a case the second you release it from its box, lest you leave it in a pocket or bag with change and keys and it comes out looking like it’s gone a few rounds with a randy cheese grater.