Dithered between 8 and 9, finally went with 9. I find Eberron to be one of the best campaign settings published--and that coming from someone who usually prefers more "traditional" fantasy, and was convinced (from advanced material) that I would hate the setting.
I love the fact that it fits together. Historically, culturally, magically/technologically, it actually reads like a world. They took all the standard D&D-isms, and took them into account in development. They worked a pulp/adventure feel, and designed the setting to accomodate. (As I've posted in the past, the world is almost a perfect metaphor for Europe between World War I and II. Indiana Jones as a half-elf fits here perfectly.)