Bought the PK2's today from another forum who also happened to be a Head-fi member over here! Been listening to these for about an hr to analyze their sound signature, and here are things I noticed (with donut pads and S639F as source):
1) Amazingly accurate and clear/transparent highs and mids. Nothing distorted or muffled, and did not notice any siblance (and I'm pretty sensitive to that). Soundstage is somewhat narrow even for buds, but give it a more upfront feeling like the Shures. It's actually very Shure-like overall, in its overall sound signature, with better highs, but definitely trumps my SE210's easily.
2) Bass definitely doesn't extend as well, especially compared to PK3 (Which I have traded with my friend for Super fi 5 pro's for indefinite amount of time), but it's the kind of bass I like which is hard hitting and tight. I connected my E3 to it and it definitely helps out in that category and has a good synergy overall, not sacrificing anything else in the process. Definitely prefer PK2 with E3 compared to PK3 stock (which with E3 as expected, isn't great) as keeps the clarity while improving the bass extension.
3) Cord and the body itself looks quite durable and seems like it'll withstand most everyday activities. Oh, and I happened to get the Y-cord version which is great (I was expecting the J ones).
So overall, it was money well spent and will serve me well as my new office earbud of choice, which means I'll be spending a lot of time with it from now on. Thanks to the seller (don't seem to have the same name over here as in the other forum) for selling it to me at a fair price and being friendly... oh, and as a nice little bonus he also happened to have the Westone 3's which I briefly demoed in exchange for my 530's, but that's for another thread.
Overall for my preferences, I definitely prefer the PK2's and having to E3 it if I happened to want more bass out of it (but I still find the stock bass fine). I'll be giving back PK3's to my friend (which I did plan to just trade with my super fi's straight up with my friend if I didn't end up liking the PK2), but I do feel that for most masses out there PK3 is a better choice with its better bass response and more life overall. But if you want more precision, PK2 is a better decision.