I'm a great fan of these headphones. Coupled to a fine system the AQ is superb and NOT lacking in bass as some complain. IMHO the DAC is often the culprit if someone is disatisfied with high end headphones. The money should have been spent on the input before splurging on hi-end phones.
I originally paid over $AUD2200 for my Sennheiser HD800S cans but see quite a few used ones on sale with $1600 the apparent lowest price. Well they can now be purchased NEW here in Australia for just under $1600 here:
https://www.becextech.com.au/catalog/hd-800-prt-p-7814.html#xml
If you go there be aware they add on extra for a supposed 1 year guarantee which you have by Aussie law anyway so make sure you delete that.
Earlier this year I displaced my HD800S with Focal Utopias but the Focals are now being repaired after a visitor operated them at excessively high levels. So I've reverted to HD800S use and am re-appraisding just how good they are. They are definitely smoother than the HD800 which I had along side the HD800S for awhile. Maybe not quite as good as the Focal Utopia but the extra cost of the Focals over the Sennies is really not worth the money IMO and I find the Sennies lighter and more comfortable anyway. But I spent the dollars so am not intending to sell the Focals (and I still have not heard the repair cost).
FYI the top headphone setup here with the Sennies is:
Roon (on this PC) -> Auralic Aries (LAN wired) -> balanced digital our via Canare D206 cabling -> YGGDRASIL DAC -> Auralic Taurus MkII headphone amp (runs too hot in the shelf so is cooled by a qiet 12-0mm PC fan at the back of the cabinet).
Note that my primary interest is classical music and there is a lot available via Roon on internet radio as well as from the 16,000 albums [12,000 classical] on the 6TB HDD with Roon.