At 100 hours, sibilance and brightness have subsided. This DAC is very smooth sounding. Detail, soundstage height, width and depth are all clearly better than the H390’s internal DAC.
Having never heard an ESS DAC before, it took me awhile to digest and assess what I was hearing. Ultimately, I found it’s not my cup of tea. It’s as though the sound is "manicured" to such a degree that all the emotion has been lost in the process. For me, emotional engagement is the top priority and no degree of audiophile attributes can compensate for its absence. Perhaps this would sound more appealing to me if paired with tubes but I have no desire to go that route.
At this point, I’ve auditioned three DACs at the 4K to 6K price point (one was used -sells for 8K, new) and have preferred the H390’s DAC in every case. Perhaps it’s time to just stay with what I like and stop paying attention to Mr. FOMO.