Just thought I should chime in. I just picked up the RCA 210 in December.
I don't experience any of these problems. I have had the box connected by both the component video and the DVI outputs. No red line, no pixel shift using either output. I am using a Toshiba 51H93. I currently have the TV connected with DVI set to Auto resolution. I did have to center the picture after swithing to the DVI, but that's it. The HD content looks fabulous. (OTA and D*)
The only issue I have with this box is the 4:3 SD content seems a bit stretched even though I have it set to pillar box. I see the pillars, they just aren't wide enough. Is there any way to control the width of the pillars? A service menu or something? I would prefer to have a true 4:3 instead of the slightly streched version.
Edit: I just noticed the horizontal line problem in 1080i. It is a very subtle horizontal line of distortion during vertical panning. Only noticiable if you are looking for it. Doesn't seem to be a solution on the AVS forums, just ways to minimize it.