Will you be around the resort enough to take advantage of the food and beverages available with concierge? We tend to spend lots of time at the resort so I enjoy booking concierge every few trips. I have not tried BC concierge, but YC is my least favorite of the disney resort concierges.
With 4 children, I think the BCVs might be a better choice. You can stock the room with drinks and snacks. With the villa you will have an in room washer and dryer which is a pleasure with kids on vacation.