I had one. It was kinda okay for some BDSM, but really for everything else it was meh. The big issue was the second law of motion. I'd thrust into my S.O., only to have her swing away and have to wait for the back swing to thrust again. Now if you understand how pendulums work, this makes for a very slow, almost tedious, rhythm, that can only be changed by altering the length of the chain from which it hangs. But even at it's shortest, you still have a 3' pendulum that is still too slow. You're basically making love to a grandfather clock.  Try to overcome it with brute strength? Nope. She ends up mostly still while you bounce off of her, making the swing pretty pointless.