My friend, Hank The Lurker, received the Motion Sound amp from BeakyBird. I went to his house and listened to it, using Hank's PSR3000. I was pleasantly surprised by the sound. The bottom was very good and the tone was well-balanced thoughout the sound range. Remember the Beakster had replaced the original factory woofer with a better one.
It was markedly better than running the keyboard into a mono amp.
My opinion is that it would be very good for small jobs, using just the 3000 and the amp.
Hank also got a Barbetta Sona 31C, and we were both astounded at the quality and power of it. I believe the 32C probably has a longer "throw", particularly with the high end, but it would be hard to fault the 31 on sound quality.
To be fair, we just heard both systems in a small room, but I think we could have broken the windows with the Barbetta if we wanted, and the Motion Sound had enough power to damage eardrums also.
DonM