We are life members. We've long since paid for the membership through the savings on fees. Yes, there are restrictions, and often you can't get the discounts on the weekend. That varies quite a bit though from place to place.
It sure is nice though to pay $15 instead of $30 or $20 instead of $40. We prefer BLM, Army COE, National Forest, National Park and State Park land for the majority of our camping instead of RV parks, but the PA membership has proven handy many times.
"You can't buy happiness, but you can buy an RV. And that is pretty close."