I actually just picked them up off waivers. I think they are a little underrated, they've had a rough go so far, but they've faced a brutal schedule.
Week 1-Atlanta, mediocre offense, Bears D looks great.
Week 2-New Orleans, elite offense, defense looks not so great
Week 3-Green Bay, elite offense, defense looks not so great
Week 4-Carolina, very good offense, defense looks not so great
Week 5-Detroit, borderline elite offense, defense looks ok other than 2 big plays
They have looked like most good defenses would look like given their opponents. I'd argue that other than Atlanta all the other teams have top-6 offenses(even Carolina) the next 2 weeks they have Minnesota and Tampa Bay, niether of which can move the ball very well at all. I've got Chicago as a top-5 defense these next 2 weeks and I don't see any reason why they won't finish in the top-10 the rest of they year. They've already played the toughest part of their schedule in my opinion.