As a long time user of Jira and its functions we got introduced to Jira Service Management. Still figuring out the structure done by someone who pulled something like Service Center functions over a project management tool.
Love Jira and maybe start to love JSM, if it becomes more customizable and I'm able to get rid of 80% of useless efficiency blockers when preparing and responding complex processes to our customers or our mail input queue doesn't blow up small images to make customer text hard to find.