Dish's UI is faster than other set top boxes, but nowhere near as fast as PC based PVRs. In addition the PC based PVRs can be customized to the user's preferences. Personally I don't like the concept of the DVR list on Dish. I'd much rather have a list that a simple right arrow opens up the episode list for each show. Then have a different background for each episode rather than the plain gray background. Use a screen shot from the episode for the background. While you are at it put a standard screen shot from the show on while in the top level list. Then allow customization of what is shown on the Home screen to allow things like local weather, a set of favorite shows so you don't have to go into the DVR list to get to your favorite shows, Maybe your favorite apps. Next I like to have a clock in the lower right corner of the screen while video is playing. Nothing obnoxious, but since I don't have a clock in the room we use the TV in this is convenient.
Of course none of those should be forced on anybody, but adding those options would be nearly impossible for DISH. I just wanted to describe which ways I feel DISH's UI is lacking.