in theory its great, in reality it doesn't work.
the device works best with small quilts.
i tested it at our LQS and used their sample quilt which was about 24 inches square and it worked great.
i went back the next day with a "typical" size quilt that i make - it was about 48 inches square - needless to say, it was terrible.
the drag was even worse that had i just quilted the quilt on my expansion table.
the drag is from the table, then there's drag from the mover - it was awful.
i spent 2 hours trying to make this thing work and walked right out the door thrilled that i didn't buy it the day before.
moral of the story, try the mover with "your typical" size quilt and see if it works for you.