I recently bought these as an upgrade to my Head Direct RE0's. The RE0's are outstanding value for money, and there is not many headphones that can beat it ... until I got my hands on the CK100's.
The CK100 packaging box is nice - very simple, and does the job more than adequately. What I noticed on it, which I've not seen in many other headphone boxes is that it lists the product code for replacement silicone and foam tips - meaning you dont have to go finding the manual for it if you keep the box. Really handy
Upon opening the box, I was a bit disappointed on the accessory front. The accessories are as follows: 3 silicone tips (S, M, L), foam tip, semi-soft case with magnetic button, cleaning cloth. Thats it. For the price tag of close to $400, I would have expected a few more accessories - airplane jack adapter, ear cleaning pick, a few more foam tips. There is enough space in the packaging box to include these.
The silicone tips do the job, but I would recommend the foam tip supplied. It forms a perfect seal for sound isolation and its very comfortable. I reduces quite a lot of background noise, to the point where when you are walking down the street you can (almost) not hear the traffic - other than the car horn, bike engine noise. At home I can no longer hear my computers fan. Some people have also recommended that I try Sony Hybrid tips, but since I do not have any (yet) I cant comment.
The sound quality is very, very good. Outstanding. Its very detailed and very smooth across the range. While the sound stage is not the widest, but the amount of detail you hear is incredible. The CK100 is simply astonishing. I'm lost for words for it.
One thing that I want to dabble on - and its a common theme this - is the (music) source. The CK100 does not seem to have its own personality compared to, say, the CK10 and the RE0. I consider the CK100 to be analogous to a transparent catalyst - for a warm source the CK100 sounds warm, for a cold source the CK100 sounds colder. I guess this stems from its initial design of exactly duplicating what is heard, but this sensitivity can be bothersome for a few.
All in all, I am very happy that I bought the CK100's.