@markmuse I too recently heard the PS Audio Directstream MK3 DAC in my home and was very impressed (even though I went with another [more expensive] option). I didn't even notice that it had I2S.
To be clear, I'm not saying avoid I2S. Sounds like PS Audio is building around it so I'm sure they've done a good job... so now you have to hope that the other end of the cable is good. I guess PS Audio Streamer to PS Audio DAC would be well implemented but you didn't like the streamer. Best of luck.
Thanks for your first hand report on their streamer.
Jerry