From my very brief listen the amp sounds quite decent but the DAC a little underwhelming. I was comparing the amp to integrated amp from my ipod and comparing the DAC to the X-Fi Forte. so its not surprising I found the headphone amp good and the DAC lacking. Onboard sound would be much a better comparison. When I have a little more time I will post some more detailed impressions.
I have always seen the Fiio products as very useful and functional products but not terribly good quality sound-wise so I would love to be proved wrong.