I have had the W4S Dac-2 for 3 years and have gotten outstanding sound, particularly after I adopted a USB to I2S bridge from Channel Island Audio (CIA Transient MK II with power module). The sound went from excellent 2D to great 3D. Still there was room for improvement versus my analog front end (which is much more expensive by several fold).
I just received my Dac-2 back from W4S following a complete upgrade to the W4S DAC-2 SE (green lights and all). Immediately out of the box I heard the improvement in the analog section (I am still using my I2S bridge). Essentially, the notes seemed more impactful, the bass is more taut, and decays of notes seem longer, perhaps because of less noise. Overall resolution is definitely better, and easily appreciated. I do not perceive a loss of warmth in favor of analytical however.
Although I am currently burning it in, the bottomline so far is that I have a big smile on my face. I was captivated to listen to music for many hours in a row without starting up my turntable. That is very unusual for me, even with the bridge in use previously. That result was my first inkling that something has changed, and changed for the better.
I am not a frequent poster, but I will add more when I confirm my opinion and find a way to cogently express what I hear, if I can find the right words. After I understand the analog upgrade, I will try to assess how the USB upgrade compares to my bridge input. I suspect they will be about even, but I could be wrong.