Patriots teams usually tend to get better as the season goes on. I believe much of their success is based upon their preparation. Early in the season they have little to go on when they play other teams, so they tend to struggle a bit early on. As the season goes on, they are able to figure out the other teams weaknesses and exploit them, while at the same time, figuring out their own weaknesses and changing them. This also helps explain why they often struggle against back up qb's, they just don't have the film on them to "figure them out".
This year their d is just so damn good it doesn't seem to matter. It seems like they got it last year by the playoffs and haven't lost a beat since. So, at this point, I am the most comfortable with this team, with the possible exception of the 0-7 team.