We use a bunch of Atlassian products (Jira, Bitbucket, Tempo, Sourcetree, IDE Connector, Jira Agile, ) but while HipChat never caught on with us, Slack hit a home run.
That said, once someone includes video group chat (a la Skype) for free we will likely jump for whoever offers it.
We were using hangouts and google chat exclusively until we finally made the jump to HipChat. We still use hangouts for group video (morning scrum mostly), and hipchat for everything else.
That said, once someone includes video group chat (a la Skype) for free we will likely jump for whoever offers it.