I might have guessed BP would have come to his rescue.
Short review: Merlin Vsm MXr vs Master
I have just upgraded to the Master from the MXr and my findings are my own. The sound is fuller and more continuous. The bass goes deeper and is more refined. I am very happy with the upgrade and have hesitation recommending it. Disclaimer: I have no connection with Merlin except appreciating their customer service and Bobbys' help.