I have generally been satisfied.
Now that I'm done being an ass...
I can't see how you would say anything other than Defense. Yes, the offense has slowed down since last season but given the fact that Morton/Kennison/Boerigchter were all injured during camp, you had to expect a bit of a slow start there... and that's where your defense HAS TO step up and make some stops. Instead, those guys made Quentin Griffin a week 1 All-Star... and in his next two games combined, he hasn't yet matched the rushing yards that he put up against your defense.
Obviously, I don't have a horse in this race but if I did, I'd be more pissed off at the defense than the offense.