When comparing Messenger vs Antox, the Slant community recommends Messenger for most people. In the question“What are the best messaging apps for Android?” Messenger is ranked 21st while Antox is ranked 28th. The most important reason people chose Messenger is:
Allows communicating with anyone who's a friend on Facebook.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Uses Facebook friends to create a contacts list
Allows communicating with anyone who's a friend on Facebook.
Pro Read receipts
Can see who has seen each message in group messages.
Pro Easy to share posts from Facebook
Integration with Facebook makes it easy to share any interesting posts from the Facebook timeline.
Pro Great UI
User interface of the application is clean, intuitive and easy to overview.

Pro Free, open source
Antox is licensed under Creative Commons with source code available on GitHub. Being open source makes it possible to make sure your messaging are not controlled by a corporation.

Pro Peer-to-peer
There is no middleman, all communication happens between the users.
Cons
Con Lack of privacy
Messenger is owned by Facebook. Based on their privacy policy, this means that any information you provide (including messages sent) are used by Facebook to profile you and sell access to your data to advertisers.
Con Lack of end-to-end encryption
Secret (end-to-end encrypted) chats are only supported in one-to-one messages, and are not enabled by default, and the encryption has not been verified independently.
Con High data usage
Antox uses the Tox protocol which is Peer to Peer, so there will be high data usage and battery drain. WiFi only mode is currently recommended for now.
Con Still in early development
Antox is still really early in development, being in beta currently.
Con Battery drain
Antox uses the Tox protocol which is Peer to Peer, so there will be high data usage and battery drain.
