This DAC sounds very good. It is also noticeable this time, ASUS has put much effort into the amplifier with, which is a deeply welcome change.
Driver Audeze LCD 3F & Sony MDR-Z7 therewith. Sounds absolutely superb. If A / B tested to twice as expensive devices. This has a pleasant timbre and very satisfactory pressure in dynamics.
Can recommend Essence One Muses Edition strongly.
This DAC sounds incredibly good for the money.
For reference, I have listened intently at both the ASUS Xonar Essence STU, Asus Xonar Essence One, and Audiolab M-DAC, which has won the EISA Award 2012-2013 for best "European D / A Converter"
Briefly, I can say that how odd it may sound, it is worth spending double the money on the upgraded Muses Edition. What you get is a much more musically, reclined and comfortable sound than the usual Essence One.
Compared with Audio Labs M-DAC, it is considerably more difficult to determine a winner, then the M-DAC has a more dynamic and somewhat enjoyable sound at short listening, but in the long run it will be for analytically, and actually provides the Asus Xonar Essence One Muses Edition just as the Essence STU, a more relaxed and comfortable sound that nevertheless highlights the most important details.
What is also worth bearing in mind is that the ASUS comes with a built-in preamp which is ideal if you want to connect directly to a power amp without risking the speakers exploded when the windows volume goes to 100%