I noticed a significant difference in my system switching from using an AES connection (DH Labs D110) to an I2s connection, initially using a basic $12 HDMI cable from Amazon. Switching from this cable to the Tubulus Argentus cable was an improvement, but more subtle. If I was on a tighter budget, I might have returned it, but I do like the sound. I have not tried other higher end HDMI cables.
I currently have my Roon Server connected to the Gaia DDC using AQ Diamond USB. Inserting the Gaia instead of connecting the Roon Server directly to the DAC was a worthwhile improvement. I have not tried connecting the Gaia to the DAC with USB also.
I currently have my Roon Server connected to the Gaia DDC using AQ Diamond USB. Inserting the Gaia instead of connecting the Roon Server directly to the DAC was a worthwhile improvement. I have not tried connecting the Gaia to the DAC with USB also.