When it comes to all fiction you consume (books, shows, movies), do you tend to remember the villain or the hero more, many years later?
Here are some variables to consider:
-Characters and concepts that stuck with you personally, for years.
-Memorable quotes or images.
-Iconic characters. Archetypes. Things you want to replicate.
-Roles that were so fucking well-acted that it can't be topped, and thus brought out the full complexity of the character.
Clarifications prior to answering:
-Villains include very bad folks that turn good at the end (e.g. Darth Vader). Partial goodness is often part of good villain design.
-Heroes include clear anti-heroes from the first act of the story (e.g. Han Solo). Partial badness is often part of good hero design.