They clearly are using different isolator feet. That could make a world of difference.
Based on the color of the DAC I suspect the silver one will sound brighter than the black one which will be dark sounding.
But the silver one has I2S connection and playing DSD while the black one is using 44.1kHz via the always worse sounding USB connection.
Thank goodness it is SMSL vs SMSL.
Hmm.... I should probably watch the video and see what they are on about.
I wonder does output impedance have any effect on DAC's?
You can stop wondering. The output resistance of the line-outs do not not affect the tonality. They can't and are probably the same anyway.
IF there really are differences it is probably due to different default or set reconstruction filters.