What Gary said about the pinbox. ;D
As for my experience, I had a rig with and without the TrailAir pinbox and I can definitely state that there is a big improvement in the ride. I've never had an air receiver hitch because they were way too expensive for me. You can always go with the pinbox and then, if it's not enough for you, go to a hitch. You would have no problem selling the TrailAir pinbox.