There is a bit of roll off on the XB90EX however I noticed especially after a good burn in. The highs are actually very good. It does not have the extended highs that are in the more detailed oriented earphones. The Carbon nanotube earphones for one. However I feel it makes up for this lack of top end sparkle with endless deep sound that are an EX specialty..If you guys want your highs with your mids and bass. While the sound is not as tight the CKS77 is actually this..This bit of roll off makes the earphones sound very smooth and tunes are ultimately very easy to listen to. Imagery is also very nice on the XB90. Recordings with up front vocals are clearly heard up front and center. Many earphones can't convey the position of instruments to vocals and the depth required for this to be right but the XB90 is magical with it comes to this making big bands and live concerts a pleasure to listen to.
You are making me want it even more. :D thanks for all these impressions, but would you mind writing a full review with pics and all that goodness?