Agreed about the JA speakers.
My test for if a speaker might be for me or not is the "can I get up and leave or not?" when listening. Some speakers just pin me to the chair making me want to listen to track after track, and the JA speakers do that for me when I've auditioned them. It's that magic clarity, warmth and incisiveness. They have the to my ears incredibly rare attribute of "surprisingness." That is, the timbral nature of voices and instruments seems so clear and distinct, that I can't exactly predict how a new instrument will sound. For most speakers once I hear drum cymbals, or a sax or a trumpet etc I pretty much know how those instruments will sound through those speakers from then on. But the Josephs seem to mirror a more life-like sense of revelation.
I remember putting on some vocal tracks - Chet Baker, Julie London, mono recordings - and I was absolutely struck at how they sounded like I'd never heard before. A certain clarity all the way through the voice to the furthest away instruments and even though the instruments were all jangled together in the center (mono) each was distinctly clear with it's own timbral voice. And the voices had a particular "that's a real person" realism. A similar experience to hearing voices through Harbeth speakers, the way Harbeth "gets' the human voice in a way most speakers don't. The JAs don't sound exactly like the Harbeths with voices but for me they do a similarly compelling portrayal of voice.