I've owned my PK2's since 2010 and for an earbud, they're pretty good. I really only listen to them when the mood strikes because they really do have their own sound. To my ear, they're very midrange forward. Vocals really pop as well other midrange-y instruments. The bass is reasonably good but doesn't plummet down to the lowest of octaves. The treble is good but it does drop off at the highest octave so they aren't strident or extra crispy.
However, the midrange is the heavyweight champ in these buds. Sometimes, it can be a bit overwhelming depending on the source but this quality imprints itself on everything you listen to which isn't a bad thing necessarily but does, in my opinion, imparts its own sound signature on the music. But regardless of that, its still a fun and lively bud that makes the music engaging but don't look for accuracy because you won't find out here. If you're looking for something more accurate and detailed in an earbud, I would recommend the Edifier P190. They look better and are better constructed. And they're way more balanced.