In my quest for a high end system, my opinion is in most cases an external DAC is of no benefit. I've auditioned the Muse 2, ART DI/O, EVS Millennium II, and Museatex Bidat with upgraded Dynaco ST70 and Bottlehead Foreplay. None impressed me to any extent. These compared to an Arcam Alpha 9 one box.
How about this? The best system I've heard, period: old Sony DVP S7000 to a stock Sherwood S-5500II integrated, with home made Utah 12" 2-in-1 speakers, DIY CAT-5 cables, DIY Jon Risch IC's. All this for <$500. I think the whole answer is component matching, and KISS to reduce jitter, etc.
Den