I upgraded from XDA-1 to an Audiolabs M-DAC. BIg improvement in every way although this isn't an entirely fair comparison since I use a Hiface 2 USB to digital coax converter to up-sample to 192 to the M-DAC. The M-DAC is just so much more full and you feel closer to every instrument and voice. I spoke to a salesman at Magnolia AV that I bought my Macintosh gear and B&W's from and he's going to get a D-100 in soon. I'll be taking my M-DAC in for some A/B comparison testing when it comes in and I let you know what my ears decide.