A general browse though the features, this app seems very nice, however I do have a few questions before I decide to buy it:
1. In stead of drilling down, is it possible to create the tasks etc. and later group them into a higher level?
Yes. You can freely copy and paste parts of the diagram, transferring them between different levels of the hierarchy. This can also be done automatically, but at the cost of loss of schedules.
2. Is it possible use custom pics for the blocks in Diagrams?
Yes. An object can be supplemented with a graphic image from the image library on the device. If the object is large enough to accommodate the image with a reasonable reduction, it will be shown in a blank area of the object.
3. Does a created file sync across devices? Although I prefer using any NAS drive, but public cloud drives are also acceptable.
Yes, the selected diagrams can be synchronized by means of iCloud, but with some limitations. You can also export diagrams and load them to the application on other devices.