What are the differences between projects and checklists?

While projects and checklists are essentially the same, there are a few important differences.

Projects:
• Subtasks can have their own priorities, due dates, tags, etc.
• Tasks can be moved into and out of a project
• Can be reordered manually using the reorder button
• If you are sorting by Due Date, the earliest due date from the project or subtask is used to place the project and to display it's due date
• If you are sorting by Priority, the highest priority from the project or subtask is used to place the project and to display it's priority

Checklists:
• Subtasks are simple items with no due date, tags, context, etc.
• Can be reordered manually using the reorder button

More information about how projects and checklists synchronize with sync services can be found here.