Task manager applications are great. They help you get things out of your head and easily accessible. One of the major issues with task manager applications is higher level planning, particularly on the fly decision about committing or not a new project. This is because you need in one look an overview of everything going one right now, including deadlines. This is something not easy to do only with a Task Manager and your electronic calendar apps. Also for what I am thinking about, a planning software is not that useful either. I tried OmniPlan for that purpose alone, maintenance is higher than I would like and I am still not convinced this is the best way of doing it.