Pros: Detail and bass
Cons: Can be fussy to fit
I bought these as a toss-up between the ER4P and themselves, and truthfully the ER4P are a lot better. these are a dual driver IEM that require a good seal to produce bass, and with the stock tips this can be hard, however, Sony's tips also work and are much easier and more comfortable.
To put them on you twist them into your ear and bend the wire around the top and then behind your ear. Then you wait for the quiet pop noise and all the bass to disappear as the seal breaks, and then you have to fiddle with them again. Eventually you get to hear your music, but of course sometimes the seal breaks more gradually, leading you to go through phases of continually checking them.
Overall a nice sounding IEM that works well with unamped players, and generally more comfortable than having Etys jammed into your brain, but they are sometimes frustrating, and don't even get me started on their cord that automatically forms any bizarre shape except for one that's useful and out of the way. If you use these, you will be wearing the cord around your chin, and that's that.