I truly believe everyone has the right to express their opinion on this issue, but for the love of God, please just call it like it is.
If you have and love the iPhone 5, it is because you love iOS and Apple products, it has nothing to do with the screen size. If iPhone 6 (or whatever they will call it) has a 5" screen, the people who love Apple and iOS will jump on it and they will love the screen size.
The thing I'm tired of hearing is the "one handed use" thing. Seriously?? Personally, I carry an iPhone 5, but my wife has the Nokia Lumia 920 (which is a terrific phone in its own right)...neither phone is physically any easier to use than the other, and that is fact.
Basically, my point is, if you love the iPhone, great...if you love Android or WP8, great. However, rest assured, the vast majority chose the phone based on what they like best in the OS or because of apps the like or what not. So yes, I'm calling BS on those who claim they chose the iPhone because it was smaller...there, I said it.