Here's part of a post, relevant to your question, which I posted on a different thread today:
I found Westone 3 was a better IEM than the SE530 SQ-wise, particularly in the treble and bass departments. Westone is known to probably have the best cables in the market, very light and yet very strong with ZERO microphonics.
Comes with no extension (big plus for me), and the plug is L-shaped which I prefer, unlike the straight one the SE530 has. I personally found the W3 slightly more comfortable than the SE530, and much more so when standing or moving about as the cable is very VERY light.
Though both the SE530's and the W3 are made of plastic, I found the design and specially the build quality to be definitely better on the W3
I then sold my W3 and got the UM3X, which I prefer over the Westone 3 re: SQ and comfort - even though the UM3X's don't have that immediate WOW factor the Westone 3's have, I soon preferred their excellent neutral, natural, and balanced sound, which makes them incredibly NON-fatiguing, an aspect that can only be matched by my custom ES3X's. The UM3X has the same cable & plug as the W3 and the fit is even more comfortable.
These atributes/ views of the UM3X -- unlike those of the SE530's & Westone 3 -- are shared by the vast majority of people who have purchased them.
The Westone 3's have a bit more bass quantity, but I prefer the UM3X which I find has EXCELLENT, punchy, yet more refined and controlled bass which CAN extend quite low.
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So, while I really liked the W3, and found it more 'fun' at first, in the end I found the UM3X better suited my taste. The UM3X shells are smaller and the angle of the nozzle is a little different from that on the W3, making the former slightly more comfortable.
The NON-fatiguing aspect of the UM3X is a big BIG plus for me, meaning I can have for much longer listening sessions if I want to. BTW, I do find the UM3X's more intimate sound with it's detailed sound and excellent instrument separation a very exciting listen. But, for people who like more bass quantity and treble the W3 will be more exciting and, therefore, the clear winner.