As someone that owns both an Android and iOS phone I think Apple has nicer form factor than the various Android options but Android has superior software. Here's my quick thoughts. iOS has caught up in a lot of the features it was missing early on (multi-tasking) but it still lacks widgets. It may not be for everyone, but I use two widgets on my desktop daily and Apple's answer to it in the notification center is bleh. I originally liked Apple's Passbook but Google's Wallet and Now surpass it in features and in some ways usability. By this I mean Google automatically creates cards for my packages from UPS without any effort for me at all. It also keeps track of my boarding passes, tickets, etc with no effort. Apple's solution requires (generally) that I open an e-mail attachment or something. Last but not least are the Google Apps, most notably Maps but it does include the others. iOS is made better by Google software and most iOS users I know use one or more Google apps. In a full Google platform though the integration is superior. Let's say I'm sitting at my desktop and search for a restaurant. The next time I open Google Now it'll have a card with that restaurant and allow me to navigate there in a single touch.
Well, it's open source, but past that, it allows installs from outside a store, has far greater user customisability, better notifications, a better desktop separate from the app launcher menu, and is far more hospitable to users having full access to the hardware they actually own.