I had unitserve, then unitserve / linear ps, then Melco n1a2 , then now Melco n1z2, connected each time as Nas.
Each step was an uplift.
When I compared nds to nd555 , both playing Tidal and Qobuz ( on mconnect app for Qobuz), I found the sound similar, but all better with the nd555. With the nd555, there was bigger scale, more defined instruments, more defined bass, and an impression of more natural and effortless sound.
It’s what I hear now with my new Melco n1z, vs the n1a. The same differences than between nds and nd555.
So , my opinion and feeling, the nds/Melco n1z/2 is on the same league as bare nd555 ( with a common nas).
Can’t compared directly, but it’s what I feel, regard of what I said above.