I have used a number of phones in my lifetime, starting with venerable Nokia mobile phones, then trying out Windows phones and Blackberries and finally arriving at IOS.
What do I like about the iPhone? It's quite simple, and it works. If you are a "tuning freak" and want to inch the last bit of performance out of your phone by installing helpful add-ons, then it is not for you. That's where Android devices shine, but then, I owned a Kindle Fire (amazon device) and another Android tablet and found they were far from easy to set up and have lots of technical issues, cross compatibility between different apps and devices and so on.
Downside, Apple phones are typically more expensive, i.e. you can only buy them from Apple, while there are lots of other manufacturers (e.g. from China) making capable and affordable Android phones.