Style, tone and language. You can forgive plotholes, flat characterization and preachy agendas if the novel is well written. Hell, I haven't enjoyed an Anne Rice story for years (Blood & Gold was the ast truely great novel she turned out) but I keep reading them because I can't get enough of her purple. She has an eloquence that allows you to be consumed by her description of a door knob (for 6+ pages).
