What are some alternatives?
When comparing Slack for Mac and Workplace by Facebook, you can also consider the following products
Slack - A messaging app for teams who see through the Earth!
Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
Slack Beta - A faster and nicer Slack built on Electron
Tandem - Get fluent together. Practice languages, anytime, anywhere.
Samepage - Easy to setup collaborative tool and file syncronization cloud application
Slack Video Messaging by Standuply - Easily record and send video messages in Slack 📹