I did a quick search but didn't see anything around here.

I listened to these at Axpona and though they had a pretty interesting sound to say the least.  On their M20 tube amp  It smooths out all the rough spots, as well as all the detail and imaging.  You might as well be drowning in syrup.  The M10 solid state amp cleans it up quite a bit, but still sounds characteristically smooth and tube-y but with improved imaging and separation.  Probably a good sound sig for all day listening like I used to do with my SE530s at my last job.

Besides that, they're darkish, have very smooth treble, and their sound stage is decently wide but without much depth.  I can see a lot of people liking these, at least on the M10.  They're pleasant, relaxing, and make hot and compressed recording sound better than they really are without killing too much of the detail.  I wouldn't touch the M20 though.  If you want more clarity without being as bright as a Lambda I suspect you'd be better of pairing them with a Stax amp, but I can't really confirm that though.

Unfortunately the guy manning the table didn't know anything about the headphone market.  I asked him if they were compatible with Stax amps and he said, "No, because they're electrostatic".

 

I unplugged them, and noticed they have a Stax plug, but without some more conformation I didn't want to run off with them down to the HeadAmp table to see if they got any clearer on the BHSE is case I blew something up.  Later I found out their bias is 550V which should be close enough and saw a post from KG saying that they were pin compatible as well.

PS:  Anax can now pick his jaw up off the floor after hearing that I said it sounded different on different amps.