Almost perfect but has one strange glitch. Lets say you are in March and realize you have a past due task say January 1 and you never got to it. When you select the quick action feature to have it due in one week - this does not move and sets the task 1 week from "today." Instead it would move the task to January 7. This is very odd because I dont know anyone who uses their calendar in that manner. I have written to the developer about this strange behavior a long time ago and this feature is still not corrected or at least have an option to schedule in this manner. Otherwise, this is an excellent app.
mdn323 about GoodTask 2 - Reminders, To-do, Task Manager with Calendar