iceScrum allows us to track our sprints and has helped us to visualize our progress in terms of velocity and burndown charts.
It is very easy to use with simple drag-and-drop features which allow you to work seamlessly without having to learn too many new things. The UI could be improved as it is not very user friendly. I would suggest users who are looking out for a robust project management tool should give this a try, it's free! We are using iceScrum to visualize our projects' progress, manage tasks, assign them to team members and release them at the end of every sprint.