After having the CUI on my HWS and my Joey 2 for a day now, I have the following observations: Performance of the HWS is a bit sluggish but generally not an issue and only noticeable in the guide. Performance on the Joey 2 seems unaffected by the CUI. The CUI for the most part is OK except for the guide which is a definite downgrade from the previous one. It is more difficult to read (classic or modern), it only displays 2 1/2 hours instead of 3 hours, it lost the 4X FF despite the graphic stating it's still there, its general format is inferior to the previous guide. If Dish addressed the guide issues I think most of the complaints about the CUI will go away.
Overall, the CUI is OK but looks a lot like many changes were made simply for the sake of change, something that Microsoft usually does.