I used RunRun.it a few years ago, in a company I worked for. At the time I was a manager of a small pre-sales team and used traditional project management tools, which in addition to having far more resources (and therefore more bureaucracy) than I needed, did not give me some useful information for team management. After an Internet search, I decided to try RunRun.it. The adaptation phase was very fast and in a short time I had availability information of the team, time spent in activity, time invested in client and, more importantly, the cost of each activity / project. In this way, I could know how much the company was investing in each project and / or customers and how much it gave us back.
Another very interesting feature that generated a lot of team engagement is the award system, based on the amount of activities delivered, well estimated, delivered on time, attendance at the application, etc. With this you earn trophies, such as the achievements of a player from PlayStatio, Xbox or other gaming platforms. I combined with my team that user with more trophies or points in the week ranking would win a lunch. A simple and cheap measure, but that encouraged the team a lot, not so much for lunch, but mainly for the "game".