I have only used the primal hardwere one (fluffer) on my wife and we found it to be more frustrating than turn-on. It was much better as a fantasy than a reality. It slid around alot and the knot, with me added in the middle was not... adjustable. So it was too much for her (which for most women it would be without a lot of warming up). So the knot just became a stopping point that was too painful to push past.
What DID work out really well though was an inflatable fluffer with me wearing a strap-on harness, dildo balls turned upwards. She LOVED that. We started with no pumps on the inflator and as she we warmed up got and wet, we added one pump and eventually up to 3 before she felt maxed out. 3 gave her a great O and we both felt like that was a fantasy fulfilled! We did it doggy style for the good deep hard fast pounding. A few nights later we tried it missionary and 2 pumps was right for her in that position and it had the added benefit of my cock rubbing along her ass with every thrust. That sent her into shivers of pleasure as well. If you get a wearable, let us know if you guys have better success!