I took the plunge and got the H3 headphones and both the solid state M10 and the tubed M20 amps. I am listening to them now (the M20 combo). I have not opened up the amps to look inside, and I am not an EE, so I cannot speak to any design criteria, but they are sounding pretty good so far. I have primarily been a sealed dynamic guy (JVX DX1000 and Denon 7000s), but i am enjoying these so far. I have not heard any Stax for quite some time (I do own a vintage pair of their entry level round cans SR34? w/ speaker adaptor/energizer that I received as a gift about 15 years ago from a friend who has since passed away). I haven't hooked them up in a very long time, but the Kingsounds and my recently acquired Koss 950s definitely outpeform them.
007 and 009 are of interest to me, with appropriate amp-age, but a lot of people comment that they are bright or aggressive or clinical or edgy, or treble-happy or any of a number of things I do not care for. (I am not saying they are, just picking up on a vibe I get from listener comments). The Kingsounds may be a bit forgiving, but they have good bottom in my rig, and are pretty dynamic, and easy to listen to.
The KS-H3 seems to be a big step up (a BIG step up) from the earlier models.
By all means please give us more comments as you get more listening time in.