When comparing Messenger vs Echofin, the Slant community recommends Echofin for most people. In the question“What is the best team chat software?” Echofin is ranked 21st while Messenger is ranked 74th.
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 Beautiful UI
Pro Powerful financial widgets
In-app widgets, such as an economic event calendar and news feed, are available.
Pro HD video streaming
Pro Mobile, web and desktop apps
Pro Ability to add pay-to-access content
You can host pay-to-access webinars.
Pro Integrated billing solution
Pro Screen sharing
Pro Chat software specifically for trading teams
Pro Talking twitter widget
Pro Admins have full moderation and user control
Pro Third-party integrations
For example, you can integrate the app with your MT4 web client.
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 Cannot customize UI (i.e colors)
Con Relatively new
Con Currently only available in English
