I think everyone's viewing preference has a LOT to do with the conference that their favorite team is in.
That said, I like CBS over all of the others for 2 reasons:
1) Their score update thing (looks kind of like ESPN's "bottom line") indicates which team has possession, whereas FOX's score update box indicates which team is leading. I can read the score, but there is a HUGE difference between a 24-21 lead with possession, and a 24-21 lead without possession. CBS gets that and FOX doesn't.
2) The blue "line of scrimmage". The first time or two you see it, it seems unneccessary, but, like the 1st down line, it grows on you. It's a whole lot easier to know the distance to go on the following play when you can very easily tell what the original spot was. Another thing FOX doesn't have and CBS does.