Zen and Zenith both have Ethernet outs, so if your DAC is network-enabled, you can use that, and it'll usually be better than USB.
This is cool as it makes them relatively future-proof. Use USB for now, and eventually, when you get a network-enabled DAC (most will go that route sooner or later), you can continue to use the same music server.
Some DACs still sound better through legacy ports, like SPDIF or AES/EBU, so this is something that needs to be examined case-by-case, maybe consulting first with your DAC's manufacturer.
Anyway, we are one of the oldest dealers for Innuos, and it's a tremendous product throughout. We also did carry Aurender and Auralic, but now we do only Innuos.
cheers,
Alex
Alma Music and Audio