I wishing the group headers were a little more prominent in the task list view on the iPhone. Comparing to Todoist or 2Do, they each do something to make the headers for groups of tasks stand out a little more and it tends to be easier on the eye when organizing my tasks by groups.

The other thing that makes the list view a little easier on the eye in these other two apps is that the attributes are consistently in the same place. In RTM, depending on how many tags you have, the length of the task name, whether it has subtasks, the information is not consistently in the same place making the list look more cluttered.