I love how Amazing Marvin allows the users to design the experience by turning on features instead of forcing a system on you. I love that there is a distinction made between do and due dates so it's highly customizable.
Now for the bad news. I find Marvin a bit clunky. I wish it felt like an outliner but when I turn a task into a project within a project, it gets misplaced in the task outline or rather "jumps" out of place instead of keeping its position. Also, oddities like the Quick Add which is nice but entering tasks using the Quick Add feature doesn't allow me to add notes to my task at the time of entry. Also, the Android app is clunky as well and the UI not as nice to work with like other apps I've used like Todoist and TickTick.