Revenge of the Sith was not very good. However, I watched The Empire Strikes Back afterwards, and was pleasantly surprised that *seeing* the backstory in Sith did make some of the moments in Empire more poignant (e.g., when Luke/Leah have their ESP moment, and the Vader/Luke confrontation), more than simply knowing the backstory had on previous (re)viewings.

More striking is how Empire is incredibly more emotionally engaging than Sith (which isn't saying much), despite the fact that the dialogue is just about as cheesy. I think there is probably an illuminating critique that could be made of the prequels based on the premise that George Lucas fell prey to the grandiose empire-building impulses of the Dark Side and thus lost any feel for the individual, but I'll leave that to a Star Wars freak to fill out. The out of control scale of the CGI sets/characters are probably the clearest example of this -- a product of ambitious control freakdom that winds up sucking the life out of human beings.

The most obvious advantages that Empire has are its physical sets (and storm troopers, yoda, et al.) with their textured, sometimes dingy, feel, and visually quieter, smaller, human-scaled, human-paced combat, which make the acting and action better and emotionally accessible, in spite of the cheesy dialogue that remains a constant throughout.
  ¶ 12:55 AM