A new update to Boomerang on Monday adds a couple of new features that can allow you to replace your Gmail client completely with Boomerang. The first is a new option that allows users of the app to receive push notifications of new incoming email. The second update allows those sending out a message to use an alias in the "send-as" box. This way your email message can be sent anonymously. With the new additions, Boomerang can do just about everything that you need it to as a stand-along Gmail client.
Boomerang remains a free update from the Google Play Store.
source: GooglePlayStore via MobileSyrup