system
A chat on /r/wallstreetbets
human
Base features actually work and are intuitive. But the killer features are the integrations. You can almost connect any tool with it. Github, Jira, Confluence, Outlook. This is basically every nerds dream.

gpt
&gt;Base features actually work and are intuitive. 
  
 Pretty much this. It's been what, a 20 year evolution of chat tools? irc, icq, aim, msn messenger, skype, linq, google hangouts.. Slack is the first one that doesn't randomly drop messages or make any conversations more than 7 hours old impossible to find.