I prefer mysteries that delve into the minds of the characters, be they good or bad. The further into their minds I as a writer go, the further my readers can travel.
That means at any given time when working on a novel, I'm a good guy or gal solving a crime or trying to survive in a world gone suddenly bad, or I'm a villain creating chaos.
In my Chicago based vengeance novel, Two Wrongs, there's a further complication. One of the good guys turns bad. I enjoyed doing that switch.
In another of my mysteries, Deadly Dreams, as of yet unpublished, a famous mystery writer and his victims become trapped in a deadly world because he can't distinguish truth from fiction.
I know there are plenty of mysteries which are plot driven, such as police procedurals, but I enjoy reading and writing those that are character driven.
What's your preference?