It's pretty neat. Try it out with this group as all groups get a chat.

Very similar layout and such. It's not feature complete yet in that you can't give role based permissions for specific channels so remember that.

It does have spoiler tagging for images which is pretty cool.

Just a neat thing I wanted everyone to be aware of.

Be advised that the new Steam Chat is in beta on Linux. You won't get it by default there when auto-updating yet.

If you don't have it yet (you'll know when you do), update Steam. If it still doesn't work, uninstall Steam and install from a new .exe installer from their website. It should preserve your installed games.