I think the 6200 is a single tuner. I have the 6412 and it is a dual tuner, which is nice so you can watch one program and record another at the same time. I used to have Time Warner cable and I had the Scientific Atlanta 8300HD box and it blew this Motorola box out of the water. Too bad I moved and can't get that box anymore since Comcast is the provider in the area. The HDMI 5.1 audio thing is a problem only when you rewind something or play a recorded show that was 5.1. Basically it just kicks it down to PCM or as it says on my Reciever Pro Logic. My 6412 only has the 12.13 firmware and I am thinking about calling Comcast to see if they have a newer version of the firmware available.