So, after having these on loan from a friend, I decided I had to source a pair, there's something about the sound I enjoy, a touch mid bassy at times and maybe a little warm but beyond that is a nice size headstage, tone, detailing levels and imaging. Also, I have never heard another IEM do Taylor Swifts vocals so much justice. It was at that moment while listening to "Hey Stephen" yesterday I just had to have a pair of W3. After offering to buy the loaner pair I am now the proud owner of Westone 3.
I'm using them amped with C&C BH / Colorfly CK4+, silver plated cable, they also sound exceptional straight from Colorfly C3 headphone out.
They don't really get along with Hifiman HM-601 though, to dark, foggy.
That's right, these phones don't pair well just with any sound source, and to me they appear to be a lot more sensitive than any other pair of IEMs I've tried in the past. When I plug these to my Asus Xonar sound card, I have to adjust the sound level to the minimum to prevent them from blowing, yet the same sound card is unable to drive my big cans (HD-600). Also, the noise floor is very high when the westies are paired with some players, indicating that the x-over circuitry may already does a great deal of amplification. Overall I must say these are likely the best universal IEMs for the price, when the grading for fit, comfort and sound combined. I made several attempts to sell them so I can try the w4, but I always change my mind at the last minute, I can't part with them...