The fact that it works out of the box, the UI is good and lots of third party integrations available. My employer recently switched from Slack since it was clo

The fact that it works out of the box, the UI is good and lots of third party integrations available. My employer recently switched from Slack since it was closed source (and management is crazy about everything needs to be open). We switched to XMPP and Movim for the web interface. Worst software I've ever used. Looks awful, unreliable, and having absolutely no support other than some hackers working on it in their free time doesn't make me comfortable.