Hipchat's downtime is atrocious.
I never see the slack app in my top battery users; I saw the hipchat app in the top battery users all the time before I uninstalled the app. I don't leaving it running for work, but not at the expense of 10-15% of my battery.
It could be similar to people complaining that Reddit or Imgur is down or unstable, but that mostly happens to Americans. So Europeans get the benefit of an overbuilt infrastructure, because the companies try to scale to the load generated by Americans.