Google has quietly released a free iOS app to help you easily transfer your data from an iPhone to an Android device, such as he says 9to5Google.

The Switch To Android app works wirelessly, which means you won't have to worry about connecting the two wired phones.
"Google's Switch to Android app helps you quickly and securely move your most important types of data - photos, videos, contacts and calendar events - to a new cordless Android device," according to the app's description in App Store.
The list of data that can be transferred does not include messages, so it seems that the application will not be able to transfer them, although it will guide you on how to turn off iMessage so that "you do not miss text messages from friends and relatives".
9to5Google states that this application is not registered in the App Store, since if you search for it you will not find it. However, you can download it immediately from this link.
If you want to get an idea of how the app will work, take a look at the 9to5Google video:
Update: The company was finally released officially the application.
