I have owned several iPhones, starting with the original one. But I switched to Android. Here's why....
To get the most out of the iPhone you have to commit to the entire Apple ecosystem - Macbook, iPad, iTunes...the whole ball of wax. I'm not willing to do that because, for me, there are better alternatives. My Android phone seems to work equally well on OSX or Windows or Linux and I think that is a big plus.
As far as the OS itself, it seems to me that OSX is getting worse and Android is getting better. I'm running the newest version of Android (5.0.2) and I am very impressed. It looks better and runs better. Battery life is very good. I have more control over how things work than I did with OSX.
All of the Apps I will ever need, and more, are available in the Play Store. It seems that there are more free ones than what Apple offers.
The iPhone is nice but I just can't find a compelling reason to switch back to it. I'm sticking with Android.