The HD looks just as good with component.
Here's the reason why the cable box "lost" the competition for HDMI connection. I originally wanted the HDMI connection because my Samsung LCD has a 1:1 pixel mapping mode called "JustScan" which is only available on HDMI input with 1080i/p sources. It completely and totally eliminates overscan. However, I found the output from the Moto DVR introduced too much edge noise on all channels. I had a green band running down the right side of the screen (note, I do think this is something that's resolved in the IMG1.6 update). So, I figured if I couldn't use the JustScan feature, I might as well just hook it up with component and free up the HDMI for something else.
If you want SD material to be passed though untouched as 480i, make sure you tell the install tech that. By default they are instructed to put it in stretch mode due to customer complaints about "not filling my TV screen." If it gets set to something else anyways, you have to access the setup menu of the box. To do so, you turn the box off and immediate hit select until the diagnostic screen comes up. Then hit the menu button and you should get the selections to change the output. Depending on the setup, you may or may not see it on the TV and will have to use the box display to set it. 4:3 override has 4 settings:
Off - upconverts to the HD output of the box, usually 1080i
480i - basically passes it unchanged
480p - tries to deinterlace it, I was not impressed with the results
stretch - I'm unsure of the resolution, but it stretches the image to be 16:9. It probably outputs at the HD resolution set.
Really, these are all the same settings as the moto HD-DVR from comcast as they are nearly the same hardware. FWIW, I had it set on 480p on my comcast box for the past year because i was using HDMI, I probably could have had better SD quality there too if I would have had it set at 480i with component.
The thing that really gets me about the SD image quality is the contrast, specifically the black level. I'm so used to SD material on cable having a black level approaching gray with speckles of noise that it really floors me to see actual black with no wavering in the image.