I've got the DJ1's. I'm not a good review person, which is one of the reasons why I've been hesitant to post a review about them.
In any case, I like them better than the HD280s. Comfort is about the same to me. They're not that comfortable, mostly due to the headband design. But I find them more comfortable than the HD280s. They don't have as tight a grip, but don't isolate as much.
Anyway, as for sound, the DJ1's, like the other closed ultrasone models, have a very wide soundstage. Bass is nice, deep and powerful, but not as strong as say, the Sony 7506s. For the most part, the mids are prominant, and treble's nice and clear. So far so good, however, I find that the frequency response is uneven in some parts. The upper midrange / lower treble seems to be terribly recessed. So some of the details go missing. I'm wondering if this is a result of Ultrasone's "S-Logic" thingamajig.... I remember reading a while back, where I think it was Duncan, who found that the HFI-650 Trackmaster also had problems with midrange, so I don't think I'm the only one. If this is true, then it means that all the Ultrasone's may suffer from recessed upper mids / lower treble..
I still enjoy listening to the DJ1's, though. Perhaps it's a sign the my ears are still inexperienced. In any case, they're the headphones I use the most, but I'm thinking of moving on to something else, like the AKG K240S's, so that I can have something that I can listen to for longer periods of time since I find don't find the DJ1's too comfortable..
Anyway, the best thing to do is to try them out yourself and see if you like them...
Hope that helps a bit!