I am not sure what it is for everyone else but for me it has to be the Fiio X5. It is the best $359.99 before tax I have ever spend on any audio gear. I A/B'ed it with my CA DAC Magic XS, thought they sounded the same. I just changed my mind fter listening to it for a couple more hours. I now realized I have never enjoyed Anne-Sophie Mutter's Tchaikovsky Violin Concerto in D Major that much, not even when the Oppo 105 was playing the original SACD but that's just going by my subjective auditory memory. What I am listening to with the Fiio is just the 44.1kHz/16 bit version ripped from the SACD. I am using the line out to the preamp's RCA input whereas the Oppo was connected to the same system but via the balanced input. This little DAP is really amazing, I have not tried its Asynchronous USB DAC function yet, hopefully it will sound just as good.
I don't typically waste my time on subjective reviews, but I have to admit one of the fluff word I hated when professional reviewer used it in their reviews, could actually be real. It is the word "intoxicating", that's how Anne-Sophie's violin sounds to me right this moment with the Fiio reproducing it. I am going back to focus on listening, the second time..