Sealed boxes....once you start enjoying them and their inherent qualities, it is difficult to enjoy traditional ported designs. Placement stops being as big an issue. Consistency in the low end is another big bonus...
I am going to give up my DM7. Too many speakers to sort out. I'm pretty sure they need the ferrofluid redone, as the treble is somewhat reticent. Lovely things though, and a bit of a design classic imo.