I love the apple phones. They’ve got great cameras, iOS is stable, great apps available. With the iPhone 6 all that remains and you get - a bigger screen which is difficult to use with one hand, but apple allows you to gently double tap(not press) the home button to bring the display down for easier one handed operation. - a faster processor, but no noticeable difference from A7 in the 5S - better camera, again not noticeably better than the 5S
Overall, its a good buy going from a 4 or 4S but if you have a 5S then stick to it. I also, noticed the phone has a heating issue becuase of a heavier processor. Heats up a fair bit. but the aluminium body helps it to cool down quickly too.