FWIW, I really love both my PM-1 and my 560. They are both extremely satisfying in their own individual takes on the music and when I put one on I just don't want to stop listening.
Many tracks favor one phone or the other, but most sound great on both.
The PM-1 emphasizes smoothness and sweet but extended highs, and it's a unique juxtaposition of silky treble, where the sometimes harsh digital edge of a bad recording is handled with finesse, but the details are not hidden, just not pushed into my ears. Any vocals or brittle highs
are detectable as there, just a bit distant, so they are not prominent and painful. It is a liquid, continuous, silky sound. But somehow I'm convinced I'm hearing all that is there in the performance: all the important stuff. The PM-1 just walks the line nicely.
The 560 also does this tightrope walk, but with more exposure of detail and texture, and shows electrostatic-like detail, texture, and speed on good recordings. But even bad recordings are handled decently. A vocal that has some digital grain will show it more than the PM-1,
and I am more aware that this is a lesser recording with some abrasiveness in the mids, buts that's just the price of truth, and sometimes the truth hurts. But the 560 still never loses it composure, and it's not like a bad metal tweeter on a speaker, so still, there is some
reticence, and the sound is not analytical (like some Wilson speakers if you ever heard them).
I think both headphone try to make things sound musical and process things a bit, and don't just let it all hang out, but the PM-1 just does it more actively.
But again, both are great and, along with the Stax SR009, represent modern headphone design at its best, and I am happy to have both, and both will get lots of head time.