[dijit]

I started my career on IRC, that was pretty good but needed a little bit of discipline and a good pastebin to work effectively.

I have used Skype for Business (formerly Lync, former-formerly Office Communicator) and that was in some ways worse than teams.

I have also used XMPP for internal communications and that was infinitely better than Skype for Business for the things you would want a chat program to be good at.

Slack is good enough, significantly better than teams but definitely what I could consider a baseline, it improves on IRC in a meaningful way in many areas and is a bit superfluous in others. (though, I suppose many people would consider the things I prefer superfluous, so, hum)

Zulip is quite exceptional, I highly recommend trying it.

I use Slack/Zoom at my current employment and it's perfectly serviceable, on MacOS, Linux and Windows.