Recs.
Updated
SpecsUpdate
Pros
Pro Pressure-sensitive touchscreen
While it doesn't add any extra functionality, 3D touch allows you to peek at apps for quick info, and perform tasks quicker than before. It almost acts like a right click on a computer. It's still relatively new, so third parties haven't all jumped on board yet. There are a lot of cool things that 3D touch can unlock such as a new level to gaming, and it all works with just your finger (no stylus required).
Pro Best selection of high quality apps
Android may have a few more apps than iOS, but there's no denying that iOS has the edge on app quality. More apps may be paid on iPhones, but it's worth the buck or two more than comparable Android apps especially if it's an app you use on the regular.
Cons
Con Limited customizability
While Android (and to a lesser extend Windows phone) let you customize virtually everything, the iPhones force you to jailbreak to get anywhere near the same functionality. Even taking control of the home screen needs use of folders for less frequently used apps, whereas on Android and Windows Phone the home screen is for frequently used apps and all the others can be left in the app tray.