My point of reference is Hopper/Joey only. I stand by my statement. I switched from DirecTV to Dish in March.
I switched from DirecTV to Dish (HR22-100 to Hopper) on April 21st. I view on a 50" 1080p plasma at 7'. I am well acquainted with the ways in which MPEG2 and MPEG4 save on bandwidth, from reducing color depth to macro-blocking. I would consider myself very discerning when it comes to video quality, so much so that I can tell a poorly mastered Blu-Ray from a well-mastered one. I used an HDMI cable for both the HR22 and the Hopper.
It simply is impossible that Dish, by down converting 1080i to 1440x1080 instead of 1980x1080 can surpass DirecTV in image quality, assuming similar bandwidth. I see evidence of this lack of detail on multiple channels, but Fox Sports Net is by far the most obvious.
On Discovery, I watched all but the last episode on DirecTV. On Dish, even the title sequence gave away slight hints of being less detailed. But there was a scene involving flocks of birds that was very busy on the screen - exactly the type of scene that would show bandwidth issues. The birds turned into a mess of white blocks. On another scene showing sunset at the north pole, the blue sky obviously consisted of large blue blocks. I wouldn't say that DirecTV's picture is perfect, but these problems and flaws were far less obvious, and the overall feeling of the picture was sharper.
On the Tennis Channel, my impression before was of sharpness over the whole screen, even on wide, full-court shots. On Dish, the image appears soft, like looking through a slightly dirty window. Even on closeups, the players appear less clear. On DirecTV, it felt like I was really looking at them. I find it hard to maintain eye focus on Dish's picture on the Tennis Channel, because it is so soft.
On HD Local-into-Local, I can't compare DirecTV's MPEG4 because it is not available in my area. On Dish, the channels are washed out and there is strong macro-blocking visible everywhere. These look like very bandwidth starved channels to me, and I will be buying an OTA tuner for the Hopper the minute they become available. They are barely viewable for me.
I cannot answer for how you might think you're getting better video quality from Dish, or even equal. But I can assure you, the only video that looks better on Dish is SD, and even that is a sad degradation from the early days of satellite television, when SD was the only game in town and the picture was as perfect as the best DVDs.
I love my Hopper, and I do not regret my decision. No one should have to suffer with what my DirecTV DVR put me through. But until Dish gets more transponders or converts everything and everybody to MPEG4, they simply don't have the bandwidth to support the programming they're carrying at a quality level comparable to DirecTV.