We went to the one in Exeter a couple of years ago. Each manufacturer only had about two cars present, so it was a waste of time in that respect, but the adaptations section was brilliant and enabled us to try 3 or 4 different person hoists before deciding on the one that was best for us.
Whereas I much prefer to go around main dealers sites when choosing a car (so that you can see numerous variants & colours etc), there was nowhere else that we could have tried all of the adaptations, so it’s a shame that most people will be unable to access these roadshows easily.