I think i am one of the first people here to get it, so i though i would post some initial thoughts
the worksmanship is great, feels much less plasticky than i would have thought.
I pluging it straight into the usb on my win 8 64bit desktop, the card lit up and started working within seconds, hovewer when i tried to manually install all the software/drivers, it said it did not recognize my asus xonar u7?!? after 15mins, i have discovered that the USB switch was set to 1.1. Set it to 2.0 and everything was fine! Installed, restarted and started listening...
Bear in mind that i never had a dedicaded headphone amp, i plugged in my v-moda m80, and started listening to some Infected Mushroom- Im The Supervisor, Kanye West -Yeezus, and some oldies; all in Flac. The first thing that i noticed was that that i could set the volume to max without getting unconfortable, Isnt the "Headphone Amp" supposed to make em louder? So i checked the setting and under headphone settings (u have to right click on the headphones, took me quite a while :D) the are 3 Gain settings
Low Gain (-12db for <32 ohms)
Medium Gain (-6db for 32-64ohms)
High Gain (0db for >64ohms)
Hovewer this was already set at max gain, i set it to medium for the v-modas, and for me 90% volume was ok (75% on low gain on my shure e500). This leads me to conclude that the headphone amp is not all that powerfull, since both these should be easily drivable... Edit:(much better with either mp3's or volume equilizer on in the dolby center, 50% volume now on low gain)
from asus.com, "Headphone : 1.3 Vrms (3.677 Vp-p)" Does this number sound about right? (I have no idea)
A pleasant suprise was that there is ABSOLUTELLY no noise at any volume/gain on my shure e500.
Bear in mind that i am not an audiophile, i just enjoy listening to music, i have found that i can hear more of the low-low frequencies, and very high as well than from my onboard sound, I have no problem with the sound this card makes, but i would rather leave this on someone with more experience, and better equipment... I quite like the software, and the surround features, and inteligent equilizer(on-the-fly equalizing, leveling volume) work quite nice, without overly changing the music. For example there is a Eq present to open up soundstage/frequency response.
If u have any questions feel free to ask