I like your app because i Control my Email with them. But take a look to the app "MinuteTaker". When You bring this together , you optimize the professionell Workflow. The Tasks from MT integratet in todoist - task will give a completely Controlling over all.
Greetings from Germany
We will consider adding the duration of tasks and similar features in future updates. Feel free to vote on suggestion such as this. http://todoist.com/Vote_iOS/