A interesting comparison between iOS and Android. I think this is spot on with regards to the UI design differences between the platforms.
One of the biggest differences in the platform for me is inter-app communication. In Android, any application can potentially communicate with another using the Intent system. It effectively decouples the communication so that as a developer you don't need to know what specific app you may be sending data to. In the iOS world, there is not a nice decoupled communication framework. This is why you see built-in platform integration for services such as Twitter and Facebook. It makes the ability to integrate new creative services into the platforms native actions difficult, in my opinion.
Still, when deciding which platform to develop for, I think the answer is going to be "both" for quite some time.