Having used all three I would say that the Passport America will save you the most money but some of the parks that take PA have restrictions on when you can stay, how long, etc. Escapees is great if you spend some time at one or more of their very nice co-op parks. They are a great value. Good Sam is useful but most of the parks that take their discount have higher rates to begin with. Unless you're likely to take advantage of the Escapees Club other benefits I would say you could get by with Passport America and Good Sam. The membership costs are low and well worth it.