I concur. From my communications with zilch0md and others, I gather that most people have been enjoying them the most out of more neutral amps than the Vali. There's also the possibility of some noise floor issues with the little Schiit unit because the PM-1 is so sensitive. Zilch0md has a Vali, but he's been using his PM-1 with the Bushmaster and the Stepdance for the most part.
However, if you really like a warm sound signature, that combination or something similar with a higher noise floor could make some sweet sounds.
Thanks ssrock64 - your assessment of my experience is pretty good, as written above. I'd like to add that the Vali does raise the noise floor a bit - it's not as transparent as the Stepdance or Bushmaster MkII integrated amp. The thing to note is that the Vali kind of softens the harshness of the HD800 treble, only as heard with solid state amps that are less than ideal for the HD800. And I find that the PM-1's resolution is fine enough that I can hear that same softening applied by the Vali, when it's really not necessary for the PM-1 (or at least, not wanted by me). The Vali surely has plenty of power for the PM-1, and it does inject a bit of that organic tubiliciousness, but the Vali is a hybrid, and although it doesn't really sound like a tube amp with the PM-1 - it does sound something like a solid state amp sitting on the far side of a very good tube buffer.
Anyway, I like the sound of the PM-1 with the Vali, but again, it holds back some of the detail that the PM-1 (and the HD800) can deliver, so as you've said, I prefer the PM-1 with more transparent solid state amps - just my tastes talking.
Does the PM-1 leak sound way too much to be used in public settings like on a train or plane...or at midnight when you can't sleep but don't want to disturb the household with music listening? This is supposedly an open can, but some describe it as sounding sort of closed, and being relatively portable for a planar, which makes me wonder about the leakage level.
A while back someone posted that they estimate the PM-1 isolates by something like 15 dB. I disagree. It's not as open as my LCD-2, but nearly as much. I can pause my music, answer my mobile phone, and carry on a conversation - with the PM-1s still covering my ears, if that tells you anything. I've tried using them at work, but it's a no go. I can hear everything going on around me. I wouldn't try to use the PM-1 on a commuter train, for example. My Sennheiser Amperiors are much better for isolation.