Let me just put this out as a 3 year Android user who has rooted every one of my phones, installed at least 50+ custom roms, messed with hundreds of themes, numerous mods, and all kinds of other stuff like that.
Now I have an iPhone and am absolutely in love with it. Why? Simplicity and reliability
As others have said, Android is much less appealing unmodified compared to Apple, and the defining point for most is the extended customizability of Android. It's true that Android is a lot easier (in a sense), has more potential, and lot more open to customization than iPhone. Yet at the same time, the customizations you do really make no difference.
In my entire time with Android, I have not found one ROM that has features that really blow it out of the water in terms of "If you root your phone, this ROM will improve your experience 200%." Developers may hint this but in the end there isn't any difference. If you use your phone everyday almost all day like I do, stupid gimmicks get old really fast. Then there comes theme, and frankly, half of them crash on you and half just don't fit well at all. It's hard enough already trying to fit the weird black theme of Android with vivid colors, and a wallpaper, all while trying to make it look simple and streamlined. iOS wins in every department for design IMO.
Then, you have mods. There are only two mods I constantly used with my Android: Viper4Android, and Netflix Super HD.
That's it. When I tried installing other mods they literally had no use, other than maybe a few timesavers such as Advanced Power Menu. But in the end, all that customizability didn't really mean much, but the drawbacks were there...
Before modding my HTC One, I could last a full day at least on one charge and had no crashes, freezing, possible bricks, etc. After numerous times trying to customize it to fit my preferences (I did not screw up any of the processes just so you know). I ended up with about a 4-5 hour charge a day and a lot of freezing, crashes, etc. The reason being is because even is Android is more customizeable, it just isn't up to par in terms of quality and reliability to default iOS even with the best ROM. Understand that when you install custom ROMs you're getting your stuff from some small developer on XDA who is not even putting their priority into it, hence there are so many bugs. And when you're trying to find the best ROM you like, bugs start building up to the point where even a clean slate won't fix some of the issues.
My point is (tl;dr): iOS wins in terms of design, simplicity, quality, and reliability. Android wins in terms of freedom and customizability, but its drawbacks when you do customize are too much at least based on my experience to really account for the pros of getting iOS.
Here's food for thought. How does iOS run so smoothly and quickly compared to Android yet it still runs on a dual-core, slower processor?
Benchmarks don't mean stuff compared to your perception of hands-on performance