Hey, I just tried out the CEntrance DACport HD with my old pair of M-100 and WOW THIS COMBO IS FREAKING GOOD!
I'm usually just listening to the M-100 with my iPhone right out of the headphone jack, but decided to try it out with my Macbook and my new DACport HD that I got at RMAF this weekend. The treble is very detailed and crisp, and less HD650-like, so less veil and better transparency. The soundstage is pretty big, and the bass is tighter than the iPhone. It's a total sound upgrade = totally worth it.