...building and releasing on Android costs 2-3x more than iOS. This is due to a multitude of reasons: less sophisticated tools, generally more cumbersome APIs, fewer exposed advanced features, enormous QA issues brought on by fragmentation...
I've developed on both platforms and only one of these reasons rings true to me -- the QA headaches of testing on many devices. IMO Android tooling is superior, the APIs are pretty much a wash and there are more advanced features exposed on Android (though not in every area). On Android you also: don't have to worry about retain cycles (and don't get me started about pre-ARC days); have access to the source code and bug tracker (a huge time saver in some situations); don't have to deal with provisioning profiles for development and beta testing.
I've developed on both platforms and only one of these reasons rings true to me -- the QA headaches of testing on many devices. IMO Android tooling is superior, the APIs are pretty much a wash and there are more advanced features exposed on Android (though not in every area). On Android you also: don't have to worry about retain cycles (and don't get me started about pre-ARC days); have access to the source code and bug tracker (a huge time saver in some situations); don't have to deal with provisioning profiles for development and beta testing.