We are active Good Sam Life Members. We belong to a local chapter in Texas, and camp monthly with them when we are in Texas. We've attend samborees in the six states of the South region and intend to do so whenever we can.
Recently while traveling up the east coast, we got a chance to attend the Georgia Samboree. We will be in New England volunteering this summer, and hope to be able to attend seven state samborees if the schedule works out.
I've gotten a Good Sam discount at one RV park in Texas. I've gotten a 15% Escapees discount at four parks in Texas which also offer Good Sam a 10% discount. (There are about 1,200 commercial RV parks which offer Escapees members discounts ranging from 10% to 50%.)
We are Escapees for several reasons, but the mailing service is the main benefit for us. We've stayed at two of the Escapees owned parks, and one of the Escapees affiliated Co-ops.
Passport America pays for itself quickly each year in one or two nights stay. We don't search for PPA parks, but often find there is one when we need it. I got into a PPA park near Daytona Speedway during Bike Week for $20 per night for three days.
That said - our main 'discount' card is a US Federal Government Senior Pass. We love federal campgrounds, especially COE. We are even volunteering this summer at a COE park.
Some day we expect to add Thousand Trails. It would work for us when we stop volunteering. A hefty initial cost that would pay for itself over a couple years.
As said above - which you join, which you use depends totally upon how you use your RV rig. One quick trip around the country, GS is a good choice. Depending upon how comfortable you are with not having specific plans - PPA can be a great choice. Don't forget things like AAA and AARP. Some parks offer discounts for those.
Always ask for a discount. You might get one.
Also don't set your plans to totally depend upon one specific RV park. Flexibility makes it easier and less stressful.