I had a great response to everyone, but my internet konked out. In any case, iPonderous, you are right - sound is subjective, but I think the 'live' sound of the CK100 is very nice for jazz and vocal - in fact, it is addictive. Some may have differing opinions however.
James, fit has been an issue for me with so many earphones. I tend to use the same old hybrid foams or regular foams on each of my earphones - they just feel and work better that way.
My choice in headphones is the DT880, so you can get a picture of my preferences. But when it comes to earphones, I actually prefer thicker, bassy phones. My favourites: SM2, Atrio, CK10, FitEars 333, FX500.
But, for an investment of around 400$ (if you get at Seyo), I would not buy another brand than AT and the CK100 is as a package, a much better buy than the Westone, UE, Senn, and even the EarSonics. The problem is that each of those could easily be crushed, twisted off and each have had their fair share of cable problems, no matter how good Westone's cable is.
The above post is a great poignant reminder that everyone has their preferences. Someone already mentioned that the CK100 and rock are not a good combo, but the above poster loves the two.
Opinions on fit and combination aside, I am totally sold on the quality both in sound and build of this earphone. Of course, my ears are 'off' and really prefer customs, but the CK100 is the closest thing I have encountered to a real 'investment' in universals. Not only will it weather the storm, but it houses a mature sound, which takes time to get used to, but is simply fab.