First, sorry for ranting a bit about the new Sony IEM's, I have good experiences with sony sound so it's exciting (for me) that they have three new IEM's that haven't been documented yet, but in a thread covering all kinds of IEM's I haven't heard, I'm sure Sony aren't the most technically proficient out there, their sound is coloured, as am I in that respect.
Second, @DaEmOnTEnTAcles, I recall some of your posts and advice to me in regards to speed in IEM's and sa5k and reading your comparisons with DBA-02 and CK10, you led me (along with joker and countless others) to the ck10's which I now use, so thanks for sharing your experiences there. I have to admit I don't think the ck10's are the fastest 'phones on earth as per my definition of speed, I think they are very good at imaging and have very high detail retrieval, also a flat FR +they show everything in the frequency spectrum, these merits combined give the impression of very fast speed but in reality I think the mids are not so fast, they are smooth and the smoothness covers up the friction of a violin string or the rawness of an electric guitar, I feel the notes in the mids are something like hundreds of fish in a river. I didn't have this feeling with my SA5k, which I found the faster phone in all respects, though the ck10 wins in detail retrieval insofar as it can rather effortlessly display every niche of sound on all frequency bands with none taking precedence over the other.
Like you, a few days ago I was considering a replacement for my ck10's in the RE252 or perhaps RE262 which looked like good candidates, aside from all the above praise I find the ck10's don't sound natural enough and I don't get immersed in the music, long story short I think it's better to compliment them rather than replace them, find something that shines where you think they err, I got lucky and did so right away and now I'm using two IEM's and I'm pretty satisfied, the difference in some tracks is laughable, I don't think I'd be having such quality listening time with the RE252 alone.
@rawrster, while I like the 10kHz emphasis, I have to agree with you, cymbals sound like a kitchen sink on the ck10's.