I have the DT880 Premium 250Ohms headphone, I've had them for 4~yrs... I never liked the DT880's with my FiiO E07K/E09K combo.. for the 1st years I owned the DT880's I used a vintage Kenwood SS receiver with them, which while solid state was fairly warm sounded pretty good. Last xmas I got a DV336SE and put (cheap) GE 6AS7GA and RCA 6SN7GT tubes in it.. mostly great results the DT880's definitely benefit from the pairing w/ warmer tube amps, However in my case my DV336 started dropping the right channel ~1month after getting it and then progressively the problem worsened... finally I got sick of it and opened the unit (CAREFULLY AS TO NOT ELECTROCUTE MYSELF...) and tracked down a poor / broken solder joint.. having made this repair (since sending the unit back to china seemed prohibitively expensive and annoying) myself the DV has been quite nice with these again.
My experience is anecdotal certainly, but if something goes wrong you are pretty much hosed as if you could find anyone local to work on it paying someone else wouldn't probably make much sense as it could easily cost as much as the unit (or more) to have it serviced, sending it back to china is going to be expensive and take forever..
I think if I had it too do over again I might have build a bottlehead crack (i wish they had (maybe they do and I just haven't seen it??) a more finished case for it... as I'm pretty rubbish at gluing wood boxes together / wood finishing .. blah blah blah.. I had concerned that the case would end up looking terrible if I had to put it together so I went with the DV.
The DV has a lot of P2P wiring and there is basically no slack in most of it... working of the broken joint was Zero fun.. but I'm glad mine works again.