I do own both CK7 and RE0, and from my experience, the main difference between the two is that CK7 is a lot warmer...it also has more bass impact than RE0, not enough to qualify it as basshead-level though. However, the quality of RE0 bass is much higher, especially when amped, allowing you to feel every nuance of the bass beats. Both have quite fast bass in this regard, it's just that RE0 is so much more detailed.
As per mids, CK7 seems a little recessed, while RE0 is pretty much neutral...no frequency seems to steal away your attention.
On the treble department, CK7 is somewhat aggressive, while RE0 never shows any sign of sibilance...CK7 on the other hand sometimes ( that really depends on the music, but there are some that I listen to that have this effect ) gets pretty fatiguing.
From the way I described above, it seems like one is a real bass monster while the other is extremely neutral, which is not true. As you mentioned, both are detailed and analytical, with the RE0 having the upper hand on these two characteristics...but for me CK7 is more of a "fun" earphone, while I prefer RE0 for more relaxed listening...