Before Android 5, IOS was ahead in terms of looks and performance. After Android 5.0 that changed, it's lot smoother and there isn't much in it.
In terms of apps, the IOS apps usually have a sleeker feel to them. In Android it's very easy to slap a crappy looking app together if you don't understand the layouts. With material design the Android apps are looking better.
So for me overall, Android is a better OS in terms of functionality. You can schedule stuff (like turn off wifi when you connect to your car bluetooth) and can set default apps for things like music. I use Google Play music and it frustrates me to no end that I have to open the app all the time in my car since the default is set to the built in App. You can also root it and do what you want to do the phone.
Having to wait for an IOS jailbreak all the time, and normally being a few releases of IOS behind is crap.
When it comes to apps, IOS apps generally has a higher polish to it.
So, each one has its good and bad, and people that proclaim the one is vastly superior to the other are best ignored.