We've been waiting a long time to move to Slack, and recently started migrating over ~2,000 users from HipChat.

Everyone is desperate for the migration to be complete, and to get rid of HipChat. A large majority had already moved their own team over.

Can't say I'll be sad to say goodbye to HipChat, it worked well for the 6 years we had it, but Slack is superior in many ways (other than price...).