Good timing, I just checked in to say how much I'm enjoying DT880 (250ohm)
To be honest guys, while I enjoy HD600 I prefer DT880 by quite a margin. I think the Sennheiser has slightly tighter bass and better treble detail overall and prefer it's mid-bass quantity however, it's a little too relaxed for my liking, those who prefer a laid back presentation might take HD600. For me DT880 while smooth is more involving and has that heft or chesty detail in the lower mids that makes them almost creamy to the ear and non fatiguing. Having had both headphones right beside me for the good part of a week DT880 gets more listening time.
My original plan was demo HD600 to assess whether I'd purchase one, however the DT880 just came from no-where and was an impulse purchase from the boards for a good price, ($150 Aud shipped), my plan of attack being if the Beyers worked out I'd save some of the $329 Aud on HD600 (the cheapest) I can get them imported to Australia from my searches.
The final outcome is my instincts paid off and the HD600 will go back to their owner while the Beyers continue to sing, actually sing for the last 3 hours now with almost no fatigue on my ears. I do however want to focus on a better amp for them and by all means maybe the HD600 could of shone better than Aune T1 dac/amp or feed from Aunes line out to JDS C421, though those are the breaks for now.
I have some new tubes coming for the Aune this week such as the Golden Lion 6922/E88CC, I'll give the HD600 another try, though my mind is pretty set, Beyers won the hook in my stable.