Slack gets a lot worse once you want to start dealing with two teams using it. With most IRC clients, I can have connections to multiple servers running, and able to see at a glance everywhere that there's activity. With Slack/Discord/etc, that involves a frenzy of clicking as you look through each group of chats individually. I can lay things out how I want, move things around, etc. Slack, fortunately, has bridges built in for IRC and XMPP clients, so I can use my already working clients instead of having to keep another web page open to another javascript-laden nightmare.
> Slack, fortunately, has bridges built in for IRC and XMPP clients, so I can use my already working clients
Unfortunately, the Slack gateway implementation is subpar. In my experience, it will send me the last message I sent before I disconnected when I reconnect, but it won't send any of the other messages that were sent in the meantime. The other problem is that group chat only works over the IRC gateway, not the XMPP one (at least I could join it from my XMPP client, but I couldn't send any messages to it).
In contrast, the old XMPP server we used would just replay messages in group chat when you reconnected, so at least you wouldn't miss anything when you weren't connected.
