Sadly, my E10 only made it one week before the 3.5mm mini plug (used as a DAC only) became so loose that the connection would be noisy all the time. I thought the DAC portion performed quite well for the price-point. But, there was also a background sound that could be heard when the music was paused. I tried many USB cables and ports, but could not resolve this issue.
I've requested an RMA and will return it to the vendor for a refund. None of my other USB DACs exhibit that background noise at all.
Based upon my experience, I would love if Fiio would put $10 worth towards better components for this amp / DAC and adjust the price accordingly. I think this would make for an excellent product that would still fall under $100 (US $$) and wouldn't have nearly as many support issues and warranty replacements taking place.