I would agree that your personal needs will determine which differences are even worth mentioning. From a normal user standpoint though, I have owned a 5s and a 6 and the main difference was size and thickness. The 6 has a noticeably larger screen and is a bit thinner. It almost seems more fragile but keep in mind for storing (pockets, purses, ect) Other than that it is mostly the same old Apple OS. I will say I think the fingerprint system works better on the 6 than the 5s but again that is only slightly. Size is the main difference here!