I don't see a DVR setting from Comcast boxes, but I haven't looked too hard. I've set it up for three different rooms in the house, where there are different combinations of TV, cable box, AV receiver, and BR player. It works sort of like a plain vanilla version of the Logitech Harmony remotes, meaning you can turn everything off and on with one remote. Although it doesn't turn everything or on with one button press -- when you press the power button, a list of your devices for that room pops up and you tap each one to turn them on/off. It also allows you to differentiate when you just use the TV as a monitor, but change channels with the cable box and change the volume with the AV receiver.
This is also a boon for my wife, who is partial to all of the lifestyle and reality shows that are scattered about the "dial" at any given time. I've set it up so all those types of shows that are currently on show up on the S4 screen when you hit On TV. Awesome feature.