The Dark Sky has a W-shaped signature, with emphasis on the bass and the treble, but never becomes harsh. Mid takes a slight step back, but it is still quite pronounced. The soundstage is quite expensive with good depth, although a bit limited in height. Nevertheless, the Dark Sky has pinpoint imaging and excellent layering.
I find that the Dark Sky did live up to its name: a thick, black space with sparkling stars. If you are looking for a fun-sounding IEM, with great technicalities and coherency, this might be the one. My full review can be found on Head-fi