Russia’s most successful Romanov ruler

Who, in your view, was Russia’s most successful Romanov ruler and who was the least successful ruler as of the onset of World War I (i.e., not knowing that a revolution was about to take place)? What were the respective strengths and weakness of both rulers?
How did each monarch understand the nature and purpose of the monarchy, and how did they want their subjects to understand it? How did each ruler define success or legitimacy, and in what ways did they meet or not meet those standards? In what ways did each monarch respond to the needs of Russia in their time? What characteristics or actions did each ruler have in common, and what features or actions made them most distinct from each other?