It's a bit strange, but there are rather many reviews on the web already available, but no one review is making some little sound comparison with other devices like xDuoo XD05 PRO, Ibasso D16, Shanling Onix Mystic XP1 or Overure XM5, it could be interesting too with Cayin C9 II/Ibasso PB5 (though those are just AMPs without DAC) or even LOTOO Mjölnir ....
Basically, I really like the concept of this iDSD Valkyrie, it can also be worth to be used with a good smartphone (with Aptx Lossless connection), assuming there is a DC input with a passthrough battery mode, like FIIO M17 have or some other devices on the market.