When comparing iMessage vs Zulip, the Slant community recommends iMessage for most people. In the question“What are the best Skype alternatives?” iMessage is ranked 17th while Zulip is ranked 26th.
Ranked in these QuestionsQuestion Ranking
Pro Secure end-to-end encryption
Pro Cross-platform within Apple ecosystem
iMessage is available on iPhone, iPod, iPad, and Mac.
Pro Supports voice messages
Short voice recordings/messages can be quickly sent, and messages can be easily dictated into written messages as well.
Pro Free and unlimited messages over Wi-Fi and data
Messages clearly indicates whether messages are being sent over iMessage (blue) or SMS (green) where messaging rates apply. iMessages do not count as SMS messages with your carrier, instead they use a negligible amount of data to send over Wi-Fi and cellular data networks.
Pro Clear indicators for message delivery and receipt
The app indicates when messages have been sent, when they have been read, and when someone is typing.
Pro Comes pre-installed
No need to download or sign up for a new service
Pro Seamlesss switching between SMS messages
Pro Friends don't need to "sign up"
You can just message them using their existing phone number or Apple ID and they will get your message.
Pro Clean UI
UI is minimalistic, and clear. And there is a plethora of stuff on the left of text box if you wanna use them.
Pro Apps and games for iMessage are available
For example, you can play games like pool or you can show someone a destination to go to .
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 Apps for every platform
Pro Easy asynchronous conversations
Its threaded model helps people working in different timezone's communicate effectively.
Pro Hosted or on-premise, with data export tools so you can migrate
Con Not cross-platform
iMessage is not available on anything but Apple devices.
Con Slow and unreliable
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.