stutters horrendously very often for my work setup (~800 people). also eats tons and tons of memory and kills my battery
Anecdotal problems
Another anecdote; your comment is the only one I've ever noticed that appears to be defending Slack. From an outsider looking in, I'm not sure why it is so popular.
It's popular because technical superiority isn't why people use software.
For example, Spotify eats 100% CPU if I leave it open for 24 hours yet I don't think I've met someone in the last year that doesn't have Spotify running on their computer.
If it helps, I don't have Spotify.
Slack takes up 1.3 gb of RAM if I don't restart it at least once a week