There's not a huge difference, but I do think D* is much more efficient and consistent in the customer service aspect. I did have some different HD channels (Travel, Lifetime, LMN, Hallmark Movie Network) but I also didn't have Spike or FX on Dish then either, so it's like a see-saw with who's the HD leader at the moment.
One thing I think worth noting, and it may be not a big deal with others, but the SD quality on D* is considerably better than what I had with E*. Maybe it was because I had to share one receiver with two tv's on their Vip722 box, but I've seen both D* and E*'s SD on the same tv and without a doubt D*'s is better. It's hard to describe, but I often got jittery and a shimmering looking SD pq with E*. But like I said, perhaps it was because I was using the second output on the same receiver.
As a matter of fact, that is also something else to consider: with E* you share the receiver if it's the HD DVR. So, for example, if you are recording something on the DVR, your TV2 will be tied up with that recording. That is something I do not miss about E*. I like having the dedicated tuner (despite the $5/month lease fee for each) per tv with D*.