I’ll add my own voice: I’ve been pretty happy with Mattermost (for both business & personal uses). It’s a bit tricky to set up initially, but once it’s set up

I’ll add my own voice: I’ve been pretty happy with Mattermost (for both business & personal uses). It’s a bit tricky to set up initially, but once it’s set up it Just Works™ — and that’s the most important thing for a piece of software in my opinion. It seems to get better every few months, which is nice. Doesn’t feel like it’s sitting on its laurels.