Hi Neutron,
I live in Dallas and have had comcast for about a year- switched to get HD locals which neither D* nor E* had at the time. HD picture looks on par with D*/E*, SD quality is average. DVR is absolutely, 100%, horrible.
Prior to comcast I had DirecTivo's, and prior to that E* with 811/508's.
DTivo : Best UI, best features. Hated the fact that you needed a phone hookup for SW updates, since i could never get this working with Vonage. Thats the only reason im not going back...
E* : average DVR, average UI
Comcast: the worst I can imagine for UI, features, functionality, and ease of use. Check the area you are moving to-- some areas (like mine) do NOT offer dual tuner DVR, which I get annoyed with daily.
I really was hoping comcast would be the winner. Im VERY glad there are no contracts with comcast, im probably going back to E* now (never thought id say that).
Hope this helps!