I do like GS, if only as a way to support this forum.
If I'm on the road more, PPA makes sense, maybe even KOA for long trips since there is a minimum standard of quality with that franchise. I've seen some pretty bad RV parks, and if I'm saying at one while exploring an area, at least KOA is a known quantity.
C2C and such are iffish... if the home park is really, really good and worth going back to, then maybe... but some of those memberships can cost so much that I would be better off buying parcels of unimproved land somewhere, having a trail to the center bulldozed, and use those as "home parks". The advantage of this is that the "park" is always open 24/7, no reservations needed.