When comparing Output Messenger vs Zulip, the Slant community recommends Zulip for most people. In the question“What are the best on-site Slack alternatives?” Zulip is ranked 2nd while Output Messenger is ranked 8th. The most important reason people chose Zulip is:
Instead of rooms or channels Zulip is built around topics. This allows you to have multiple conversations at the same time without conversations interfering with each another. It also allows you to reference conversations without clutter.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Built in screenshot tool
Easy to take screenshot within the app.
Pro Keep remote employees and multiple offices in sync
Pro OTR (Off-the-Record) messaging
Pro Active directory (LDAP) support
Pro Favorite users list
Pro Screen sharing
Pro Voice & video chat
This software provides easy access for users to make voice/video calls with high clarity.
Pro Accessible from anywhere
Pro Browser support
Pro Helps keep track of different conversations
Instead of rooms or channels Zulip is built around topics. This allows you to have multiple conversations at the same time without conversations interfering with each another. It also allows you to reference conversations without clutter.
Pro Free and open source software
Zulip is free and open source under the Apache 2.0 license.
Pro Easy asynchronous conversations
Its threaded model helps people working in different timezone's communicate effectively.
Pro Apps for every platform
Pro Hosted or on-premise
With data export tools so you can migrate.
Pro Intuitive interface
I struggled with Slack, never finding the settings I like to adjust. With Zulip never had such issues.
Cons
Con Remote Desktop is slow while accessing through internet
Con No End-to-End Encryption
Not even for private one-to-one messages, let along group chats.
Con Takes some getting used to
As most chat software uses the concept of channels or rooms, getting in the habit of splitting each topic off in a separate category can require some getting used to and discipline.