I'll try to keep it short as I don't want to off-topic one of my favorite threads.
Basically, it's a music server with a optical output. Antipodes, the $10K music server, uses the same backend software. So all the processing and battery power is used on the rPi0 side. This allows a separation of the backend and frontend. For my frontend, I can use an app on my iPhone or a Apple Watch. Being a Raspberry Pi, I can also use infrared remote control as long as I have a infrared receiver. Since I miss the ergonomics of the Tera Player, I use this remote than can be controlled from inside one's pocket a la Tera Player. The rPi is powered by a USB battery bank. The app can be closed once you launch a play process, so saves the iPhone battery. App is optional if you just use the remote.
Since it's optical, it's device-agnostic. I can use for Mojo, Hugo1, Hugo2, DAVE, TT2, 2Qute, Qutest and any future iterations of Chord devices as long as it has an optical input. It's software-agnostic as well as there are also Android and Android Wear apps for this purpose.
The rPi0's built-in WIFI is turned into a SSID router allowing any device to connect to it thus allowing UI software control.
For the sound, it's amazing. I used premium USB cables in the past with Hugo2 and was never overwhelmed by Redbook CDs. Now I understand why Rob Watts mentions RBCD > DSD. Having a proper source makes a big difference for my RBCD enjoyment. I use a Lifatec glass optical cable with this build. Zero RFI makes a extremely black background.
So in a nutshell, it's a Wireless Hugo2 setup with some Tera Player influence sprinkled in the middle. It's like having a Desktop Music Server + Chord in a portable package.