Didn't know where else to put this and didn't want to start a new thread, so I will just post it here.
No revelations if you have looked at the frequency response charts and imagine the CK90Pro with the treble in better balance to the bass.
Bass: Of course, the CK90Pro has more bass and warmth, and while there is more bass slam, it is still fast bass. On big bass passages neither reverberate they way a dynamic does, although the CK90Pro is closer. This it to be expected as they are both BA designs; which presentation (dynamic vs. BA) is right is open for debate (I choose to enjoy both). But the CK90Pro does have an added warmth that makes certain music very enjoyable such as the piano. And due to the added bass in the CK90Pro, the bass details are more apparent. For example, one of my test track Epica - Indigo has faint ticking at the beginning that I can not hear with every IEM. But I know it is there because some reproduce it. Surprisingly the CK10 doesn't while the CK90Pro does at the volume level I was listening at (crank the volume up and I can hear it).
Mids: With the comparison time I have given these two, the mids seem very similar. I might find more differences with additional listening. My problem is I got too much new gear too quickly.
Treble: The CK10 is the treble king here as it has not only more treble energy, but the treble detail reaches out and grabs you! The treble detail of the CK90Pro is analogous to the bass detail of the CK10 mentioned above; sometimes it is difficult to hear it all at quieter volumes. The CK10 treble sounds lighter and airy most of the time, but with some of my female vocal metal (i.e. Nightwish, In This Moment) for example, the treble is a little too sharp. Of course, this is due to the recording.
Imaging: At first I thought the CK10 was the clear winner, but upon specifically paying attention to how the music is portrayed in 3D space, they both do a great job, but do id a little different. The CK90Pro seems a to push everything forward a little compared to the CK10.
Soundstage Width: Again I thought the CK10 was the winner, but the CK90Pro is about on par.
So, which is better? They actually compliment each other and depending on the song, I usually distinctly preferred one or the other. But to me, I can just blindly grab one or the other and have hours of music enjoyment. Now, if AT (or anyone) can make an IEM with the CK90Pro bass and CK10 treble (and the mids from either), I am going to grab that!