I am using this app from last 5 to 6 years.
I have got a very nice experience with this app. Good point of this app is we can use this app for sim messages as well and for Facebook messages also at the same time.
We can add many facebook accounts and after that we can switch our account to other account which we want to use.
This app also have feature of secret conversations which we can use for personal chat.
This app have audio and video calling feature and we can add friends from messenger without using Facebook app.
We can block message from messenger.
I think this is a very nice app.