Got the efi82's (with 840 pads) yesterday and love them. I can't go into details about how much better than are, or what they are better at, as I'm too much of a noob in the audiophile world. They just seem so well-rounded in every regard. I currently own the ad700 and takstar hi2050, and the somics easily beat them. I no longer own my d2000, but from what I can remember, these beat the denons in certain aspects.
The only thing I dislike about this headphone is the housing. I never liked DJ-style headphones. They just feel cheap and plasticy. Also, there's a slight hot spot on my head from the headband when I tighten them up. When I loosen them to get rid of the hot spot, they feel a bit too loose on my head. I just wish they were in a better housing, but for $40+ it makes sense.
As far as you can remember, what is better on the Somics vs the D2000s and vice versa?