Got mine today.... .. I'll try to describe them the best I can given my understanding of the sound adjectives.
First impressions out of the box vs the DN1K
Same red spacers, tips as the 1k.
Diymodded Ipod 5th gen --> Pure silver LOD --> JDS Labs C5
-Better imaging, instrument separation, layering
-More balanced, balanced, balanced - vocals sound more centerstage vs the instruments
-Clarity up a bit, better detail retrieval
-A bit more airy than the 1ks
-Tad bit toned down bass, though at the same time tighter- still the same texture
A/Bing vs the 1Ks, the 2Ks have this ability to envelope you while you listen to them. Especially for live performances, the 1Ks put you in the front row, while the 2Ks put you and make you feel like you're in the front row. However, as what I felt like on some tracks with the 1Ks, sibilance remains the same. I do wear the thin-bored tips which may promote it a bit.
From what I remember vs the T-PEOs H300s, the H300s win in bass, clarity, detail retrieval and treble extension. DN2Ks take everything else.
That's it for now, given all the accessories included (the ear wings, different tips etc.) I bet sound signatures change with each combo. But given the price paid, and for those who got them from other means, definitely a truly awesome IEM that you will not regret purchasing.