CKS line improves the main problem of traditional audio technica products which was bass. CKS50 did not focus on the quantity but the quality of bass, it does not have the quantity for hard rock music but it was tight and powerful enough for pop-rock also it still have the sweet mids like audio technica do which makes my perfect choice for j-pop female vocal.

IE80 has a warm sound overall,crisp high and punchy bass. The "bass knob" was the best part for me since I am not a basshead so I only turn the knob to halfway. many people said the main issue was isolation but it really depends on where u used it, for me the isolation was enough in train and buses(maybe I dont like total isolation).
To me the carrying case seems to be too big for IEMs