CK100 has been with me for almost 5 days now. I am still amazed every time I hear a song with these phones. Its mid and high range are I think what Shure tried to achieve with the SE530s, only that the CK100 has really achieved it. The sound is so so so transparent on the CK100 that it surpasses SE530 on liveliness, and its detail goes head-to-head with ER4P at the same time. It is purely the sound from heaven. Never would I have imagined such sound would come from IEMs, but it does - on CK100.
Mind all of you that CK100 does require some power to back it up. On my newly bought Nokia N97, CK100 still sounds sweet and transparent but it only has about 60% of the true power revealed. (My Westone 3 and TF10 Pro are not that source dependent.) But when I connect CK100 to Cowon D2 (mod to D2+), it sounds purely fascinating and is much better than when it is connected to N97. From D2 you can hear that its bass is actually tight and deep (much deeper than SE530 connected to Cowon D2), and has more bass than TF10Pro quantitative wise. Still it can't beat UE11Pro, W3 and IE8 in terms of quantity of bass but it would certainly be enough for pop song listeners.
Here is the deal - you get the best mid-highs you can ever get from IEMs with CK100, with the sacrifice of a little bass quantity. It is not only good with female vocals but with all kinds of music (except orchestra and some really bass-heavy electronic stuff like "minimal"). I would seriously recommend it to anyone who likes music. To me, after years of searching and going through er6i, er4p, SE530, TF10 Pro, UE11Pro, Westone 3; CK100 is the IEM that I finally came to know what I was looking for.