Pros: Light, versatile, good laid-back SQ
Cons: Power treatment not the best, susceptible to EM interference, generic Thesycon Driver doesn't support 176.4k sample rates
Looking back at this unit, it was excellent for the price. It had great connectivity (coaxial S/PDIF output, both 3.5/RCA full scale outputs, 9 Vrms headamp) despite only being USB-powered,
The OPA1611-based 9Vrms headphone amplifier was smooth and laid back, sometimes a little too laid back for the detail lover in me, but very pleasant to listen to. It had low and high gain, and <1 ohm output impedance, so it paired well with multiple sources, equally at home with both my IEMs and my HD598. I compared it to the DACPort, and I thought the Class A headamp in the DACPort was slightly more refined, but got pretty hot, whereas the D7 only ever got slightly warm. The D55 (Hibino iBasso Japanese only version) was more spacious sounding, but not any better as a DAC.
I could always carry it around with me if I wanted to, as it was super light. But the enclosure was tough too. The silkscreening and matte finished showed practically zero signs of wear despite everyday use.
It served me well!