Who is using I2S cables?


I've been reading / watching info and trying to learn about I2S. Several manufacturers offer I2S connections (Topping, Pro-Ject, Jay's, Denafrips, Singxer, Raspberry Pi?...). I2S has been used internally for years (mainly internal CD to DAC connections) but some components have I2S connections. So, I'm confused and curious. 

1. Are you using I2S cables? What has been your experience? 
2. What components are you using I2S to connect?
3. Are you using an HDMI cable or so-called bonafide I2S?
4. Where did you purchase your I2S cable(s)?

Thanks!
128x128dreas
Currently running an I2S between PS Audio cd and dac. To these ears it sounds superior to the xlr or coaxial connections. The I2S cable in service was the one provided with the unit from ps audio.
I have a Jay’s Audio CD transport and DAC and use an AQ cable for the i2s and it works well.
Thank you @jaytor . And yes, I understand a little bit re. the different configurations @lalitk mentioned. Which is why I was asking for smarter folks recommendations :-) 

If I read correctly, you noticed a significant improvement from AES to a $480.00 I2S cable https://www.highendcableshop.com/product-category/i2s-cables/ ?

So, two follow up questions: 

1. any chance you had an "A-B" experience with a high quality USB A to B connection and is the upgrade expense that big an improvement? 

2. re. a properly configured high end HDMI vs. the Tubulus Argentus I2S, you could tell a significant -- i.e., it was worth it -- improvement? 

Thanks much! 
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.