Having used a few apple and android phones, I believe their operating systems have different design philosophies in regards to what they are trying to accomplish. In my opinion, Apple's iPhone aims primarily to be a communications device, focusing on email, texting, calls, and social media apps. Apple perhaps limits their phones in regards to what they can and cant do, with a focus on not allowing things found on a computer like software customization, and a file and downloads manager. Indeed, you probably wouldn't change the software found on a phone connected to a box with a cord, so why would you want to change the software on your iPhone?
On the other hand, many but not all android phones allow computer like things of installing apps from wherever instead of curated app stores, custom operating systems, and a folder called downloads. Perhaps all this gets in the way of ones phone being a seamless communications device, many an android fan would argue that they do not.
Do you see your smartphone primarily as a communications device, or rather a pocket computer? Do you prefer the "it just works" of iOS, or the customization of android? Do you believe your phone's operating system affects the way you view your device?