Summary: Bought this for a SFF LAN machine that needed something better than onboard. I use Sennheiser 350s and I was happy with the sound of this card. The USB extension is nice. On Win 8 you have to download beta drivers for this to work.
Pros: Small size, great sound, decent price
Cons: Could have a better amp but that is a limitation of USB
Summary: I bought it as a cheap way to get around routing audio from a program through this thing while having the rest of the system route audio through the speakers/headphone jack an it worked beautifully. However, this thing is so big that plugging it in directly blocks the other ports on my laptop. Using the included USB Extension solves this problem and everything worked out great. As the title of this review states; I just would have liked it to be a bit smaller.
Summary: Recently the front headphone jack on my rather expensive computer failed. Its a full sized case and while I could have reached around to the audio plugin on the motherboard I'd rather not be troubled with it (being I use the phones on several devices). This a good solution. The USB jack is on top near the front - very handy for access. As for the sound quality - I'm not a big audiophile by any stretch.
Summary: Ordered this when my laptops headphone output stopped working. ONly got sound out of speakers. So I disabled the drivers for the laptop sound, installed drivers for this card, and rebooted. Now I can connect my headphones thru this sound card and hear what I need to without disturbing anyone else. Will work beautifully when i start recording music/songs via DAW.
Summary: It's been awhile since I have came to this amazon screen... I had bought the XonarU3 in December of 2012. By looking at the date, you know how long I've had it... For some of you who may not know exactly what the main purpose of this product is: The XonarU3 was BUILT to be maintained in a laptop system, not a desktop system(HENCE the USB). If you need a soundcard for a desktop, you are better off buying a PCI card, as USB audio is worthless if you have a desktop...
Summary: I have a laptop and after getting some high quality Sennheiser headphones, i wanted a better sound setup. For around $40 it was either this or the creative card and i decided to spring for the Asus card. Im glad i went with this card and i could easily recommend it to anyone looking for a simple upgrade for laptops. The card removed the constant hiss i could hear before and it has a wonderful equalizer and surround sound processing.
Summary: I love this sound card. I've used the Creative Sound Blaster Recon3D THX USB before that costs twice as much. However the Xonar U3 is better in almost every way- price, performance and size. Good job Asus.