I've had the opportunity to spend a couple of hours listening to the CWIV in a less than ideal setting (smallish room), driven by a very high end tube amp (forgot the brand, price was around 12000 for an integrated)
It still is to this day one of the most musical systems I've heard. The midrange and treble on the IV is far, far better than any previous version. The CWIV communicate Music with a warm, inviting musicality and a big sound. It's not your overly transparent Magico speaker, but it certainly is refined enough for all but the most picky ears and communicates scale, micro and macro dynamics, and textures with ease.
If I was in the market for my last pair of speakers, the ones that will accompany me to the grave, I would seriously consider the CWIV.