I've had my Comcast Motorola 6208 connected to a 62725 via component at 1080i. Yesterday I changed the connection to DVI to HDMI. This is at 720p. I did it primarily to make sure the DVI connection worked before my 30 return is over, but I also wanted to free up a component connection.
It's pretty subjective, but I think the picture looked better with the component connection at 1080i than at 720p with the DVI component connection.
I Thought that I had read here where the DVI input is converted to analog and therefore probably wouldn't be any better than the component input.