I did a lot of research on this before taking the jump to a full Lumin U1 and just added an X1 power supply. Night and day compared to my Node 130 with upgraded power supply feeding a Denafrips terminator plus. Granted I don't have direct experience with the Zen but imagine that and the Node aren't far off.
The Lumin app takes some getting used to but overall it's an amazing setup, and for me an 'end game' on the streamer side. I also listened to a Lumin U1 mini and T2. If you're patient, look for the full U1 used. That's what I did.