Summary: The Westone UM2s strike me as being a good and thoroughly thought out design. Considering the price of nearly $300 these earphones are only suited for audiophiles and perhaps musicians that crave high quality.
Pros: Dual-driver solution, Excellent fit, Superb comfort, Bass and midbass performance, Balanced mids, 50" cable, Copes well with microphonics, Well suited sound signature for most music genres, Sound stage, Open sound, Well worth the price, Detailed sound, Sufficient amount of bass for most music types
I must say the UM2 sounds better than the UM3x which I sold shortly after few months. In short; it sounds more articulate,airy and more expansive. The UM3x sounded too bloated,closed in and collapsed to me; the soundstage was too narrow and the UM2 doesn't share the same trait which is great.
Pros: Good separation, pleasing midrange. Airy and engaging
Summary: I upgraded from a pair of UM1s because they didn't deliver the bass I wanted. I used these while practicing the bass and listening to my iPOD. The dual drivers really deliver a high fidelity sound with hard to believe bass for the size.