A Kanban style board. Slightly more advanced, it has more visible task status can show important tasks and those waiting for an answer or blocked. The in-process state allows column per task role (instead of having a general In Progress column). The UI is also pretty responsive (adapts well to various screen sizes). The fast task input is most welcome.
Pro Responsive UI
UI adapts well from small screens to really large ones.
Pro Project metrics
Pro Wall mode
Useful to show tasks on a large monitor within your team's area.
Pro Visible status or each card
Each card can be marked as Question, Blocked, Urgent/important, In progress. Colored by named label, etc.
Con Possibly shutting down
In 03-2015 they announced shitting down but due to the popular demand to keep the service they're re-thinking about it.