I got this idea from Aurender CEO in a interview. He does not let hdd do the playing. OK for storage, but hdd hands off to SSiD for play. Thus the question as to whether the vault has ssid and therefore a better player?
I think this level of details are less important in low end or mid end equipment. Try something and see if you like the sound regardsless of the tech inside. Read what others like, like the Node 2i.