I dont think that any satellite company has a better picture than any other. It all depends on who is broadcasting it. a digital picture should be the same on almost any DLP monitor. Now if your carrier has a bad connection, well thats different. We used to have Charter digital cable and I could see some "static" in the picture sometimes so we went with DirecTV.

As for the size, I would say go with what fits best in your place. If you go too big and sit close to the TV, it wont look as good.

I think Texas Insturments makes all the DMDs for the DLP TV's out there right now.