The USB on the Pi has some issues. A lot of devices need to use an external, powered USB hub because the board can't supply enough. Your ethernet is also going through the USB hub.
The issue with usb on rpi is that it's unstable. It can drop messages. For ethernet it doesn't mean much, because packets will be retransmitted, but for audio it means sound will occasionally stop for a moment. It's very annoing.
The Schiit Modi is double the cost of the Wolfson card and has no audio input capabilities. Seems like for uses outside of an HTPC the Wolfson card provides a lot more flexibility.