I looked into this several times in the course of my flight training as a way to fly cheaper, build time and get access to good aircraft. There are a lot of things you have to do for them that are not required by flying clubs and FBOs. My conclusion was, the deal varies depending heavily on the way the local squadron does things. If there is a strong, well run and well-staffed squadron in your area, there will be a lot of chances to get access to an airplane and the rules will be more flexible and costs more reasonable. But if the local chapter is not strong or they are not allowing much flexibility in the rules, it may not be a good deal at all, and this is why I never pursued the one in my district.

I had a friend who was deep into it at one point, so much so he bought one of the older 172s. It was a gorgeous plane and he rented it to me at cost, it had lots of power and was rigged oh so nice. It had the original CAP paint scheme still on it so I would fly into an FBO where there was a girl at the desk and say, alright we have reports fueling is being done incorrectly here so I need to inspect your methods. You can start by demonstrating on this 172. Several of them fell for it, but I passed all of them. It's fun to watch a 20-something fueling a high-wing airplane.