I just wanted to say that I am here in Irving, Texas, and I went to my local Comcast facility yesterday morning and upgraded my box. I currently have an analog tv, but my old digital cable box did not have SVHS out. I just was unhappy with the picture quality, knowing that there was at least one step up I could use.
Anyway, I called Comcast the day before to see if it would be possible to upgrade, and they said yes...just bring in the old box. So, I went in this morning and walked out with a 6412, brought it home and connected.
My first impressions are very good. First of all, the picture quality has improved, as I suspected, going to SVHS connection. Second of all, I noticed the change in the guide and menus, which I love. I hated the old yellow guides with advertisements on them, very distracting and ugly. Third, the channels do seem to change faster, although there is a slight pause, becuase the PVR unit starts recording it so you can pause live tv.
So, like I said, I am very happy with this unit so far. I will record some stuff tonight and see how that works. I do not have an HDTV, so I cannot compare full hdtv resolution, hopefully after the first of the year I can get me a nice tv.