Windows Phone Vs iOS Comparison Chart have posted a long comparison chart of Windows Phone Mango and iOS5 features. Built-in funtionality can work either way, enhance the user experience or prohibit 3rd party innovations. I think every OS should balance their feature set so that 3rd party developers can enrich their respective platform. Take a look at the chart below,

Windows Phone Mango has the most built in features ! !

via: mobility digest