I think the Luxury & Precision W2 Portable USB DAC/Amp is the best dongle I have ever used for my computer, iPhone, and Android devices. However, there are a few reasons why it is not a fit for me:

• I have a high-end DAP that I really, really enjoy
• The update process takes a lot of work since I don't have a Windows machine, just linux/OSX. Virtual Box and I don't need to spend more time together
• It doesn't have a UAC1 mode for my gaming systems

That being said, it sounds amazing. I got a great silicone case for it and it is in mint condition. Price includes PayPal fees and shipping in the USA. Check out my feedback - I love buying and selling on the head-fi community.