We're trying to decide whether it's worth it to become "Disney Club" members, even though we get certain discounts with the DVC card. What benefits would we get in addition to the DVC discounts if we joined the "Disney Club?"
The primary benefit is that you get a discount on park passes. DVC only offers a discount on Length of Stay passes which tend to be impractical for DVC'ers who will visit WDW often. You also get discounts at DD stores (I believe including World of Disney) that you do not get with DVC. Assorted restaurant discounts may or may not be the same as DVC -- I never really analyzed them.
We kept our DC membership when we joined DVC in '98. Used it for discounts on park admission both at WDW and Disneyland, at DD, and the great National Car Rental deals - good all over the US.