I hate audio shows. They all turn up the volume too loud because the next room is so loud and they realize everyone's ears are ringing so they have to turn it up to get through that. Thus the audition means nothing to me.
You are listening at 70 dB, even with insensitive speakers, that's less than one watt. So the question is, is the first watt from the other amp better than the first watt from your amp? Probably not.
I think you are experiencing just want they wanted you too--at excessive volume the dynamics stood out.
Jerry