Omnom ive got both. To sum things up,the xb90 is an upgrade over the ckm500. The bass reaches deeper. The mids give out more details. The highs are smoother and has more details. Not to degrade the ckm500 but the sonys are just on a higher level. The presentation and soundstage is also superior on the sonys. That said, I still enjoy both with the xb90 getting more ear time. It is that enjoyable. Just pure musical bliss. Oh so engaging! I really think this is due to the 16mm drivers being utilized to its maximum potential. A bass rumble ive never heard in any iem. It is simply a basshead audiophiles delight! Just like drinking Hennessy Cognac. The more you listen, the better it sounds!
Hey dude just curious if you've heard/have/had the cks77 also. Would be nice to hear another opinion on how they compare to the new sony's