If you use only one email app on your mobile device and are happy with it, stop reading. But, if you find any shortcoming in it, or if you have two email apps you use, read on. Actually, you don't need to read on at all: Just install Blue Mail and your life will improve immeasurably. Blue Mail is not a third email app. Rather, it will be the only app you use. It will receive for you all the emails sent to whatever other email apps you are using, and let you send and reply directly without ever having to access those app ever. As important, it will eliminate any shortcomings you have with your other email apps such as address book issues and conversation view (in Gmail). In short, it's fabulous. You give up nothing and gain everything. It's what kids these days call a win/win.
Link to Blue Mail for Android