I haven't done an analysis of the methodology that Football Outsiders use for these measures, but I thought worth sharing in case someone wants to look at it more closely (and I'll try to look myself when I have more time).
If you look here you will see some stats that suggest that, once you control for the defenses we have played, our offense has been the 7th most efficient offense in the country. (!)
On the bad side, if you control for the offenses we have played, the analysis here suggests we have had the 117th most efficient defense...
I think this is the most extreme statistical differential I've seen between our offense and defense, but it seems clear which side of the ball has been producing.