I prefer tight grammar and fast-moving plots, belivable dialogue and consequences that respect the fictional universe's integrity. I have more time for funny than grim, and more patience for short fiction than long fiction.
Much to the amusement of my writing group, I write far darker fiction than I prefer to read. I set my characters up to fail, lose, hurt, despair, stumble, and eventually succeed - even if the best success is a good death.