Just started using it.
A killer for me is that there is no badge on the app icon so I have no idea how many things I have to do without opening the app.
The application badge shows the number of task due 'today'. And of course, as you mention, to be in the today's list the task have at least to have a due date defined.
Secondly, when I do open the app, it opens to 'today' which has nothing in it (almost all my to do's are not scheduled but outstanding) and I have to go to categories to see what there is.
For most people using a GTD like application, what does matter is to have at first glance the number of action to be done for the day. That's why the Today list is shown by default.
DiGk: if you could add a badge and allow (?in settings) for the opening page to be 'categories' that would help a lot
I'll keep in mind to include those into the next release.
A setting parameter to define which panel is default one if users want to bypass the actual parameter and the application badge to show the today task or the overall task.