Quote: A lot of that was more of a comparison of the W4 to the UM3X. The biggest difference between W4 and ES5 is that the ES5 still has better treble extension and presence (like an HE-6), while the W4 seems more laid back in the treble (like a v1 LCD-2). The ES5 also seems to have better micro-detail, imaging, soundstage, and bass impact than the W4. They were shooting for the ES5 with the W4 in the way that they tried to the get the phase alignment right for good imaging, but they didn't really make it all the way there. I actually still prefer my ES3X a little more than the universal IEM I own. I don't want to make it sound like the W4 are like an ES5 in a universal shell, but I do think that they are a little better than my UM3X, which are a little better than my W3. And their design philosophy for the ES5 was extended to the W4. There are a couple of people who have JH5 and W4, and I seem to recall they preferred the JH5 a little more. There seems to be a definite audible advantage to customs, due to the custom fit and having properly tuned sound tubes in the ear canal portion.