Then the output the best Comcast supports is 1080i I think so choose that I assume. Although the option before 1080i is "native" and the lady in Comcast I was talking to did not know what that was since this is a new box. Their tech person also didn't know.
If it's like others that option will send the same resolution to your TV that the original broadcaster transmits. Not all broadcasters transmit 1080i. If you select 1080i then the STB will up convert the signal to 1080i regardless of what it receives. Unless you use the 4:3 override then SD channels will be in 480i or 480p, whichever you select. If it were my STB I'd take a look at all my favorite channels in both 1080i and Native.
The next thing to change is the 4:3 override. Should I leave this to off? When would you want to have a 4:3 override?
If this is set to Off the STB will up convert SD channels to 1080i if that is what you have chosen above. And believe me, unless Comcast does a better job than Dish an up converted SD is bad. I was so happy to see Rubicon in HD last night. Dish just turned AMC HD up last week.
Finally they also allow you to change the video sharpness from 1 to 5. It is currently on 3.
A matter of personal choice. Change it lower and higher and see which you prefer.