You need to understand that 'digital cable' is not the same as over-the-air (OTA) Digital Television, better known as DTV.
Digital cable is similar to the DBS providers standard definition channels, both are over-compressed and not of high quality.
In SD mode, your local DTV stations will have a better, less-compressed signal than both DBS & digital cable.
In HD mode, the quality of the local DTV stations & the DBS providers are about the same, unless the local stations are multicasting, in which case the HD quality suffers.
Many members have influenced their local DTV stations to not multicast, when transmitting HDTV programing. A call to the station management can be very helpful in this respect and also let them know we are watching and are concerned, which is a good thing.