CK10 has flat response on the bass and mids, but have a very emphased high. CK100 has a upper-mid-forward signature, less emphasis on highs and slightly rolled off on bass (below 80 Hz is most noticeable IMO).
Both are very good at detail retrieval, but the CK100 has the advantage on mids and highs are very refined, allowing fatigue-free listening for hours. But CK10 presents it more in-your-face.
The CK10 sounds like it's dissecting the music, separating every instrument, making easy to focus in one instrument. The CK100 makes music sound more like a whole piece (not in a congested way, but more like a better idea of how the music should sound, if that makes sense).
When I had both with me I compared them many times, I found that the CK100 a little more rich and full, because of their mids.
Build quality on both are top notch, being the CK100 the better. CK10 is easy to drive, unlike the CK100, which needs a good source and files, I found to have synergy problems with the computer soundcard but they are perfect with the Galaxy S. They were horrible with the N95, sounding a little cold compared to the GS and pretty noisy.