IOS 8 developed by Apple Inc. whereas Android L developed by Google.IOS 8 belogs to OS X, UNIX OS family whereas Android L belongs to Linux OS family.
IOS 8 source model is Closed, with open source components wheareas Android L source model is Open Source
IOS 8 is programmed in C, C++, Objective-C whereas Android L is programmed in C, C++,Java.
Talking about customizable, Android L can be customizable whereas IOS 8 customizable is Limited unless jailbroken.
The IOS 8 kernel is not open source but is based on the open-source Darwin OS whereas Android L kernel is open source.
In IOS 8 default browser is Mobile Safari whereas In Android L default browser is Google Chrome (or Android Browser on older versions)
IOS 8 available for many ios supported devices such as iPod Touch, iPhone, iPad whereas Android L support many phones and tablets including Kindle Fire(modified android), LG, HTC, Samsung, Sony, Motorola, Nexus, and others.
IOS 8 messaging service is provided by iMessage whereas in Android L it is done by Google Hangouts.
In IOS 8 voice commands is available and it is carried out by Siri whereas in Android L voice commands is done by Google Now
In ios 8 map is default supported by Apple Maps but in Android L it is done by Google Maps.
In ios 8 video chat is carried out by Facetime whereas in Android L it is done by Google Hangouts.
In ios 8 app store is provided by Apple app store and has about 1,000,000+ Apps whereas in android L app store is provided by Google Play and has about 1,000,000+ Apps.
IOS 8 is suppoted by apple devices whereas Android L is supported by various brands of Google, LG, Samsung, HTC, Sony, ASUS, Motorola, and many more.