I just got the DAC2. Powering it with HDPlex 300's 12v output. Probably the best DAC I've had in my system.
I replaced the dead 9V batteries with EBL 9v Li-ion batteries. I can't tell the difference either using external or battery. Sounds the same.
Also, feeding the DAC with DDC with external clock via audio dedicated PC.
The reviews I've read are mixed probably because they were lacking in terms of signal and/or power.