[bookwormAT]

http://developer.android.com/design/index.html

[corporalagumbo]

It's shocking how much clearer and more inspired this guide is than the equivalent for Windows 8. Makes me pessimistic about Microsoft's competency.

Also, the Google guide is much nicer to look at itself than MS's.

[Mythbusters]

This is still a recent development. It never had this originally. Besides going by the ugly apps, it hasn't had much impact so its ineffective at best.