With half the season completed, we have enough data to draw some conclusions:
USC Total Defense national rank: #62 (349.8 yards per game)
UCLA Total Defense national rank: #68 (358.2 yards per game)
Not much difference. UCLA gives up more points, but that's mainly due to their awful offense (#130 out of #132) which puts the defense at a large disadvantage by giving opponents much better field position on the average than USC.
But we need to take strength of schedule into account by looking at non-common opponents:
USC played Utah St. (#19 Total Offense), Michigan (#119) and Wisconsin (#53).
UCLA played Hawaii (#105), Indiana (#4) and Oregon (#18).
But Utah State's high ranking is misleading since they played USC with a backup QB and when they got their starter back, they averaged well over 500 yards in the last three games boosting their ranking quite a bit. So UCLA, on the average, played stronger offenses.
Now look at common opponents:
LSU gained about the same amount of yardage against both schools. But look at the totals when they played common Big-10 opponents:
Penn State and Minnesota yardage against UCLA: 566
Penn State and Minnesota yardage against USC: 891
But this isn't really about whose defense is better, it's about which DC is better. Lynn has done a good job, but nothing that lives up to the enormous hype he came in with. The Trojan defense is trending steeply downward, with an especially poor performance against Penn St. For example, how do you let one player catch 17 passes without making an adjustment? Some of USC's decline can be blamed on losing one of their better defensive players, but that is just indicative of the importance of personnel for coaching success. On the other hand, UCLA's defense is improving. Malloe has done an excellent job considering he lost four players now on NFL rosters and another who most likely will be in a couple years. The conclusion is that you can be satisfied with either one.
So there is ample evidence that Lynn wasn't such a huge loss for UCLA and the huge gain for USC that many here feared, the point I've been trying to make all along. This should make Bruin fans here happy. That is, except for one, who judging by his classless insults and angry personal attacks, this wasn't really about Lynn, but other issues he has.
I rest my case.