Thank you all for your responses. I decided to arrange for a one on one in house direct comparison. The differences to my ears are that the Mac was more neutral and transparent. You could hear greater detail on passages, both simple and complex and better leading edge on notes. Also, human voice sounded more real. On the other hand, the ARC had more bloom, bigger soundstage and could be overwhelmingly beautiful. Much more drama. MAC = film. ARC = technicolor. I'll take the MAC but I could understand the ARC point of view. Also, MAC is one beautiful piece of audio jewelry.