Sacks:
GB: 27 (in 550 pass attempts)
NE: 33 (in 541 pass attempts)
NO: 31 (in 540 pass attempts)
Completion % against:
GB: 60.9% 7.7avg
NE: 63% 8.1avg
NO: 56.9% 7.1avg (For giving up the 28th most yards, they don't allow too many passes completed against them, also note that 6% difference only turns into 40 yards on average)
NE clearly has the worst pass defense of the three. But, they have the 5th most turnovers and the 3rd best differential. They also seemingly have the best pass rush, or at least make it to the QB more often in passing situations.
I'm still not going to say this defense resembles anything good, but for those who think it is clearly the worst in the league, I would take it over NO and GB's defense this season.
28 extra possessions is simply huge. No matter how many yards you give up, when your defense gives the offense 2 extra drives per game on average (if they don't score on the turnover) you'll have a hard time losing because of the D when our O is as efficient as they are.