When I first started out as a full timer I joined 'all' of them. And found that 'none' of them offered any real benefits.
Good Sam - 70% of the GS C's I stopped at said they no longer offered GS discounts yet the GS sign was still out front.
Good Sam - Then there was the GS CG's that claimed the discount was already in the posted rate. :R And you will NEVER EVER be able to stop all their junk mail until you die...and then I suspect it will still keep coming.
Passport America - Every CG I was near had restrictions up the wazoo. Had to be the second Monday of the month, the forth Wednesday of the month or when the moon was in the rising phase etc. and NEVER during any holiday, to get the discount.
I couldn't fathom a weekend RV'er ever benefiting from all their restrictions. Unless you like staying a Tuesday and Wednesday anywhere
Escapee's - Good for the full timer that needs a domicle. But as far as discounts go they have but a couple of their CG's across the US and many are resorts at high CG rates. Certainly not worth it to the weekend RV'er.
Never renewed any of them. Threw out the woodalls book too. I get to a town I want to stay over night at and google the CG's in the area.
Over the years I have always found wonderful CG's at great rates this way and over half of them where not listed on any 'official RV site'. :C