for me, I like iOS because of the support it gets from Apple and third party developers. Most if not all apps almost always comes to iOS first or gets updates much quicker. (Even Google updates its apps faster on iOS than Android)
THIS. As a former Android owner, this was one of my biggest gripes. It's not just that the apps get updates quicker, it's the entire way that Android is handled as an operating system. Apple releases an OS update, and you install it and there it is. Google releases an OS update, and it goes out to the phone makers, who modify it for each model of phone they make, with the phones they think will make the most money first. Then it goes to the carriers who make even more changes, possibly breaking functionality in the original OS or that the maker changed. Then it goes out to you, weeks or months after Google released it. If you're sporting a slightly older phone (meaning anything that didn't release as a flagship in the last couple of months), it could be 6-12 months before you get an update. And if that update breaks functionality, no one bothers to fix it, because hey, you could just buy the flagship or run a ROM that will also break functionality, but hey, it's different functionality. (can you see the steam coming out of my head?)
Apple updates the phones they make for a least two full annual cycles, often longer. App makers update their iOS apps, and when they do, the apps actually work the way they were designed. And if they do release with bugs, they fix them.
Yes, Apple could learn a thing or two about allowing customization. But if I have to choose, I'd rather have a consistently working phone over one I have to spend time fixing and/or ROMing. I'd rather be able to own a phone as long as I want, not be forced to buy the newest because nothing works on my 6-month-old device. I'd rather not have to jailbreak just to make backups of my stuff (no, I'm not kidding).
And all of that is just why Android sucks. None of it covers how well the devices within the Apple ecosystem work with each other, which is another great point about owning Apple devices.