I have the 100T. I am very pleased with it. A friend had the mac and I heard it on a few occasions. To me, the cayin has the edge. I have 4 ohm ProAc's and they love the cayin. Finally, cayin is a better value.
I am also using the Cayin A-100T with the ProAcs. I had the A-88T before and then upgraded to the A-100T. I did not compare with the Macs but I am very happy with the sound. I matches very well with the ProAcs.