Pros: Mid centric, smooth sound, no sibilance, no mid-bass hump, vocals are upfront, price. Durability.
Cons: Not much treble extension. This makes difficult the details to hear in low volume, big, uncomfortable design, poor isolation.
These earphones are quite big, so if your ears are really small, you can face some problems. Comfort is not great either. Finding a good fit is a little challenging. Don't expect Westone like ergonomics. The cable is good I haven't seen microphonics so far. It has a detachable cable. Overall, it is a good durable product. But comfort and isolation is not great.
The Sound: These have dual drivers. For the price you pay, the sound is really good! These have powerful bass response but not overwhelming the other frequencies. And mids, yeah, where these earphones shine. Vocals are clear and warm, enstrument seperation is fine for the price. Mids are taking the front line of the sound. Treble is not sibilant by any means. But don't expect airy treble like top of the line flagship IEM's. Detail level is good, especially when you consider the price.
I used Shure SE215's and Westone UM1's. And I think these are the best sounding of the three. And the cheapest!
But Shure's and Westone's, comfort and isolation wise, are clearly better then IM50.
For 70$, I can't think any better IEM's than these.