Fidelity Online have published their LUMIN X1 and LUMIN Amp review.
During the review Michael Vrzal states:
X1: A streamer to convince all streaming skeptics. Lumin's top model simply makes music and impresses as a valuable high-end component.
In terms of sound, the X1 shows the same signature as the Lumin Amp. It is transparent itself, always at the service of the music. It was immediately noticeable how three-dimensionally this streamer / DAC plays.