I'd go with Chicago because they definetely have a better defense. That said, I don't think either is a good play because both the Eagles and the Saints have proven this year that they can score alot of points against almost any defense. See what defenses are available on your waiver wire/free agent market. If there are any favorable matchups (defenses playing games against teams with no offense) pick that defense up and drop Dallas. Dallas isn't that good anyway. They got beat by the TEXANS right out the gate. Whatever you do, DO NOT drop Chicago...they'll only get better as the season goes on.