The build quality of the main unit is outstanding

There aren’t many all-in-one units that offer as much in versatility in such an elegant, compact design, with good overall sound quality, and the DAC is quite good

The audio quality is amazing and it has, so far, easily driven all of my headphones (I don't exactly have any T50RP to drive...yet).

But I do think it’s fair to say that the X1s is competitive in sound quality with the better solid state DAC/amps in the price range, and it does do a good job bringing out good qualities of your source (the source is the key)