Se535 vs Westone Um3x

I haven't tried the UM3x, but have demoed the W4 and SE535 back-to-back (albeit for a short period of time). The W4 should be close-ish to the UM3x at least when compared to the Shures, especially based on what I've read of the UM3x. I can't give you a ton of details, but I can tell you for sure that they have VERY different sound signatures.

The Shure is quite mid-forward... too much so for my taste, at least upon first impression. I would have liked to give it more time, but didn't have the chance to. The W4 sounded much more natural to me and I feel that it would fall into most people's preferred sound. Basically, I'm saying I think you made a good choice unless you really, really like forward mids. I like nice, flat, warm mids, but not FORWARD mids.

The UM3x are better pick because there mids, bass are supperior compared to SE535 and highs have more clarity too (created for stage monitoring) and SE535 for consumer daily commute(to me sound different from orignal Shure E500).

I'd also agree that the Shures' treble is too rolled off for a top tier IEM. It is nice for fatigue, but not for extension.

I felt that UM3X is way too rolled off in the treble with some tips, like the foam comply. But it was fairly well balanced with silicone tips. From my experience, multi-driver BAs can change their sound greatly depending on how you fit them in your ears - too much so IMO. I think SE535 is more balanced and lively sounding, but with the wrong tips and fit, the midrange can become overly present and shouty, the highs can sound harsh and the bass can sound detached from the rest of the spectrum. UM3X never sounds harsh which is a good thing in a way and also never sounded obviousily incoherent either (although I think I could still hear the lows, mids and highs playing a bit separately from each other). But it also lacks the sparkle and fun factor that SE535 possesses. One could call UM3X more of a studio monitor, while SE535 sound is more audiophile friendly IMO. With the UM3X, I noticed that the bass, while tight and deep, seemed to suffer from some "plasticy" case resonances - it wasn't very noticeable, but there. SE535 has a somewhat better composed low end IMO, but does lack some sub bass presence compared to UM3X. Overall, SE535 is forward, lively and even aggressive sounding in the highs, while UM3X is softer, smoother, but may seem too dark and boring depending on tastes, fit source, etc. I believe UM3X has the potential to sound more recessed and veiled in the upper frequencies and more boring than the more forward SE535.