Since Microsoft launched the closed beta, the company has also made several improvements to the experience including the ability to set Cortana as the destination for the home button press. Now access to your personal digital assistant is just a button-press away.
You will also see a few differences between what Cortana can do today in her "native" environment (Windows) and in the app on Android. For example toggling settings, opening apps or invoking Cortana hands-free by saying "Hey Cortana" are only available on Windows for now.
Cortana on Android is currently available in the U.S. only, but Microsoft is planning to roll it out to other markets.