How important is USB-I2S DAC connection?

Ken, you are right of course. My ears are fair but I am not technically really savvy.Obviously there are many ways to reduce jitter and to make for good sound. At the end, most of us make our decisions intuitively, if we like it or not.

Detlof...thanks for the comment. I've heard a lot of good things about Steve's gear. Gear such as Zanden, AMR, etc., are superb machines, so I've heard.

My point is while I2S interface may bring you closer to the "real thing," there seems to be implementation/execution side of things that dictate the "subjective" performance of our hobby. As an example, I've heard real nice feedback about Northstar DAC, Scott Nixon DAC, Audio Note DAC, and MHDT's Paradise+ DAC, but not all of them have the I2S interface. Some even prefer the non-I2S DACs to the ones with I2S interface.

Anyway, I'm just trying to learn. In the end, I guess what sounds good, is good. Unfortunately, I can't hear all the gear out there.

Ken,
Actually it is not what you think, it is what you hear and the I2S interface does bring you a tad closer to the "real thing" in a well designed component, like Steve Nugent's gear or the Zanden, just to mention a few.