Apple has been known to be restrictive when it comes to anything related to their devices and software. By being a close source system, iOS users cannot fundamentally customize anything on the iOS. On the contrary, Android gives users their code source and fully permits modifications.
The bad side to open source is that there tends to be less regulation on what comes out, be it trash apps or spyware on roms.
Expert developers can easily identify security holes in the Android then post malicious apps and other programs on the market to monitor your phone. Whereas, Apple fully regulates what gets on the markets.
Although quality varies between Android devices, Apple iOS devices are known to be considered premium products.
4) Vendor Lock
Notice how up until now only AT&T has the iphone?
5) Limited devices
With iOS, you are limited to Apple products and services. Android has countless vendors that produces phones running on the Android.