the first time I tried an electrostatic headphones I did not believe what I heard: the amount of details the Stax L700 delivered made my literally cry. the next one was the SR-009...
 
i tried them with the Stax SRM-727 II,

SRM-007tII​

 and a German made Mal Valve Headamp (mark II?).
 
 
design
i would not say that these are the best looking headphones on the market, however, I still like the way they look a lot. it does feel premium. the headbands are well made and it fits to most heads. the pads are soft.
 
comfort
I personally find the Stax L700 more comfortable, however, the SR-009 is also very comfortable. and it is lightweight. especially compared to the Audeze headphones.
 
soundstage
these cans have a smaller soundstage than the Sennheiser hd800, and it is not that much in front of you as with the hd800, rather next and behind you, but the quality of the soundstage is better with the Stax. The hd800 is almost too loose, too unorganised, too wide. The sr-009's soundstage makes sense. everything is at its right place on all the three axis.
 
imaging
just as the soundstage, the imaging is fantastic. everything has its own aura.
 
details
this is where these electrostatic headphones are waaaay ahead of any other headphones (I haven't tried the 2016 Orpheus though). I even tried them with a 320kbps mp3 track too see how they react and I never thought that such a poor source has so much detail (information) embedded. There is such a big discussion about music compression, however, I believe that there are barely any headphones out there that can reveal all the details even in a poor audio source... 
 
highs
the highs sound soo true and so amazingly clear and detailed, it is hard to describe.
 
mids
the same goes for the mids. they are amazing.
 
lows
this is probably the only point where I can complain a bit. though they are well extended, I think that the average quality of the lows are falling behind the other frequencies. I think they could be more detailed and more articulated. Sometimes I had the impression that these cans don't care much about the lows that much. sometimes they felt "empty".
 
speed
these cans are extremely fast. almost too fast.  
 
general characteristic
they are bright and for my taste too bright. So I had to try them with different cube amps until I reached the point where they were soft enough for my ears (the Stax 

SRM-007tII​

 cube driver failed to soften them enough but the Mal Valve was able to do it). The Stax SRM-727 II made them more organised, more "on the spot", but too bright for my taste. they are very-very musical but analytic as well. a perfect combination of the HD800 and the LCD-2.
 
price
in Europe you have to pay about 5000 Euros for these, in the US less, and in Japan about 2500 Euros. That is a huge difference. They are an amazing deal for 2500 euros (that is approximately the price for the HifiMan HE-1000).

i was very excited to try the hd800s together with the Oppo HA-1 amp and dac. i thought that it is going to be a clear improvement over the legendary hd800. however...
 
look
i like the black matte look of this model more than the silver paint of the hd800. hopefully the quality is better as well: some of the used hd800 look ragged, the paint comes off.
 
comfort
i am one of those who find the hd800 uncomfortable. for some reason, the hd800s is more comfortable: at least it does not push too hard under my ears.
 
soundstage
one thing i really liked about the hd800 was it's very wide soundstage (although it is too wide, or in other words: unorganised). the new hd800s completely lost this feature. now the soundstage is much smaller on all the axis.
 
imaging
just as the soundstage, the imaging is way less powerful than on the hd800.
 
highs
my (and many others) problem with the hd800 was its overpowered highs. the new headphones are much more easy going with them. the highs are more in the background, more part of the whole. they are way less annoying, though they lost a lot in terms of excitement and detail.
 
mids
the same goes - though the difference here is not that big compared to the original hd800 - for the mids. they are more easy going, however, they lost a lot of excitement.
 
lows
this is probably the only point where i see some improvement over the hd800. the lows are more extended and detailed.
 
price
you have to pay 25 percent more for the new hd800s. for me, in terms of sound quality, it felt like a cheaper version of the hd800. the only extra over the hd800 that comes with the headphones is a balanced cable. go and try the Stax L700 with a Stax driver: for a similar price, you will get a way more superior sound quality.