I am using Kaizala for last three months. I run a group with 500 odd people, and it is ready to go big. It is one of the best messaging apps both for private and team use. The number of users it can hold in a group is just remarkable. In every respect, it is better than the alternatives for me. Some of the top features include no storage limits, functional design, end-to-end encrypted chats, extra functionality like cards where one can add training module, polls, quiz, and many more.
Pros:From simple messaging to creating groups/channels. A complete communication app. Simple, can hold a huge number of members
Cons:Nothing negative about it till date.
Used this for sales team
Pros:Free app with good enterprise features.
Cons:getting users to install wasnt very easy
Trying this is a pure waste of time.
Pros:None so far
Cons:Another rebrand of an existing product by Microsoft, another clone, yet something for old enterprise that thinks that Slack is for Hipsters.