I2s over USB? I assume this is a prototype as it makes no sense, I2s is best over RJ45, secondly HDMI, but for best sonics RJ45 by Neutrik is the only way to go. Maybe Lukasz will offer this over USB to realise the potential? I'm interested to hear more about this implementation on this DAC as I think this is where many DAC's and users are missing out.
Ayon for one use I2s over RJ45, there is quite a long list in fact, and many also use HDMI now, but the problem with I2s is there is no pin out standard, so not all combinations will work together unless you order a bespoke I2s cable to marry the two specific pin outs. Of course this is not for the box swappers but for the long term users.. In addition Pink Faun produce a I2s PCie card for servers, which can be specced for whatever DAC pin input arrangement is required, see link below:
The Pink Faun I2S bridge realizes a high-quality I2S (PCM) connection between the music computer and the DAC. Read more here.
www.pinkfaun.com
This would be my choice, without doubt.
BR,
Paul