The Burndown chart is very simple. It is easy to explain, easy to understand. But there are pitfalls observed in the way teams adopt and use the burn-down chart for tracking the Sprint progress. The most common issue is of the Cliff-hanger Burn-down chart. When we first started off using JIRA Agile, we used Epics to specify large feature-sets ,stories for the individual capabilities of the larger feature, and technical tasks (JIRA sub-tasks) for individual work items.