For the cost of membership and annual fees, plus the cost of actually camping at their campgrounds, and then all the limitations, restrictions, and rules about when and when NOT you can and can NOT ... well... all that money can be used camping in a lot of State, National, and Private parks that offer a wider variety, location, and less "guilt!" Yea, guilt! If you don't use the membership for whatever reason (say you get sick and are unable to go camping for a few months) ... it's money wasted. When you free-lance camp, the most you'll looses is a portion of your payment.
The idea of being restricted to a specific set of campgrounds is just nauseating to me. There are way too many other locations to visit!
If you REALLY want to stay in one of those campgrounds, I suppose they make allowances (of course a price too) to visit there. Still, there's no obligation then to fork over annual dues and such! Too restrictive in my book.