Re: Speaking as someone who knows bugger all about Slack..
I prefer to use Flowdock instead of Slack as I find it simpler to integrate and, after all, integration is why we use Slack, FD etc. I want a tool that enables me at a view to see who has pushed what to where on GitHub, Gitorious or BitBucket or who has updated work time spent on a Jira project and, above all else, who is actually working 'WFH' rather than Playing Fallout 4 ' WFH'.