I own the DAC portion of this system. I think it is superb and would not hesitate to recommed picking this up if it suits your needs. The rest of the post is detail on my system and listening style so you can make your own conclusions.
I use the "cheapo" power supply supplied with the DAC and not the fancy separate one that is part of this drop. I put quotes around fancy because it's a better power supply than most device supplies. Anyway, I run it through a late 80's Denon receiver (MSRP $1200 in 1989). Bought used on ebay for $100. Super clean, super low THD amp in the receiver. Lots of power. Big, fancy caps, big transformer, nice power transistors, physically built in Japan. Then into 10 year old, but undamaged cones of Bose 301's bought new. It's a simple setup and the first standalone DAC I've ever heard. I'm partial to very clean electronica and trans-ambient techno. I have mild autism and am very sensitive to distorted sound. I also like simple low instrument count music tending to have a female singer - all miked well and mixed carefully and cleanly. Favorite album of all time is Switched on Bach by Wendy Carlos if this helps to gage my concern with clean sound.
This DAC is spectacular. It is exceptionally clear using either speakers or headphones (Audio Technica ATH-M50x). I can't convey just how clean and technically perfect the sound is. You can also turn up volumes to levels far beyond what is safe or even tolerable and nothing - no distortion, no weird edges to the sound, no clipping. I can stand outside my front door and go for max on the amp using the remote, and nothing. Just loud, but as clean as low levels. The sound just goes up to insane levels and sounds just as clean. I've never heard anything like it. At normal or low or very low levels the sound is wonderful. From what I've read, DAC's generally sound a bit "deficient" at the very low end. I don't want to get in an argument with people about how that's not the case with their system, that's just what I've surmised. Maybe I'm wrong. Whatever.
I suspect most devices like tape decks, CD players and such introduce a touch of low end amplification before the signal even gets to the receiver or preamp. It's well known that when you want to sell a particular stereo at a store, push up the low end on that system using an equalizer but don't tell the customer. People always fall for low end boost. But standalone DAC's don't do that. That's the whole point. Flat as can be, no THD, no crosstalk, so it's up to you to modify the signal in your system after the DAC or using playback software if possible if that's what you want. My system isn't built for BASS. That said, now I have super clean sound, I'll be buying a lower end ($200), but decent, powered, tight subwoofer to pick up the slack at the low end.
I'm sad more people aren't picking this drop up. If I needed the headphone amp, I would. It is solid as a rock. The drivers work on win 7 pro. It generates very little heat. It's small. Very pretty. Simple. So far, I like SMSL stuff so much I just got the M8 for our bedroom setup. I wanted to hear the difference, needed another DAC, and massdrop had it available. I should point out the Panda DAC chip was specifically designed for subjective sound quality, not objective specs. That's what the advertising literature goes to great lengths to say. I believe it after hearing it. The specs are great, but other chips are somewhat better. But according to the chip manufacturer, the Panda DAC was made to sound good, not win a spec sheet battle.
The only thing I wish was different about my setup is that I had the high end power supply that comes with this drop.