My 880's (600 ohms version) were delivered today. I can't compare them to the 250 ohm version, but I have had a pair of the dt 770's (80 ohms) for several years, and these wipe the floor with them. They are quite diverse and work well with a lot of types of music. These are going to be my new mid-fi jack of all trades. I love my q701's for pop, rock jazz and classical, but for metal, they just have too large a soundstage and every thing feels too distant. The 880's are much better suited.
I also picked up a pair of the 990 pro's. I was really disappointed by the 990's. I can honestly confirm what everyone else on this forum probably already knows, the 880's are the best out of the 3 beyer mid-fi cans!
Hmmm...having the DT770 80, DT880 600's and DT990 Pro's, I would not agree. I would say that their model ranking is quite precise. DT770 < DT880 < DT990. Despite someones personal preference of a sound signature, in a direct comparison between the DT880 and DT990, it is clear to me that DT990 are technically superior in virtually every way. They have a bigger soundstage, a more airy sound that is fuller at the same time, which leads to having better sound separation. The overall sound resolution on the DT990's also seems slightly better, they sound cleaner and clearer, and are slightly more detailed as well. I never found the DT880's particularly detailed, at least not in a comparison to something like HD650 or K701. DT990's do have more bass and treble than the DT880's, but that's not bad. I think they take the DT880's, keep all the good parts of it, and upgrade them to a higher level, plus add a bit of bass weight and a bit more detail in the highs.