Pessoa Training System or Balanced Training System

Has anyone here used the "Pessoa Training System" or "Balanced Training System"? If so, do you have before and after pictures of your horse or pony? I just want to see what kind of results people are getting using this training device? Here's a link to what I'm talking about; Pessoa Training System - Dover Saddlery.

I have a balance training system (very similar to the pessoa) though I never used it a lot to see results.

I don't know if the Pessoa works better than standard methods of teaching your horse to use its hind end, but I do know someone who made one herself rather than spend oodles of cash on one from a tack shop. I think the DIY Pessoa thing cost her like £10. So if you're going to use one, find someone who has one, study it, and make your own. Then if you decide that it doesn't do anything, you're only short a tenner.