With all of the horror stories I keep reading on this board about failed cable card installs, I thought I'd share my good experience. The Comcast guy showed up in the middle of the 2 hour window with an M card (and a few other M cards as backup). We plugged it into the Tivo, the Tivo recognized it and took me to the cable card setup menu, the Comcast guy called up to initialize the card, and a few minutes later the Tivo automatically went to the acquiring channels page. Then I did a full guided setup to get a new channel guide and all the new channels (including the HD ones) showed up. I'm getting all the channels I should be getting and the picture quality is really good, especially MojoHD.