Another factor contributing to the Pumas' dip in performance was that their last 2 games were officiated by referees that had a very strict interpretation of ruck laws, which negated them their strongest area and the ability to play the game to their favoured tempo. That said, they barely did any player rotation, especially in the forwards and that told yesterday.
New Zealand is just at another level, even if they rarely set the world alight earlier in the competition, at least not by some of the past standards. Even yesterday, they hardly had any ball in the first half, but then wiped the floor with Boks at will in open play. They have a bunch of guys in their 30s or thereabouts (Woodcock, Mealamu, Hore, McCaw, Thomson, Weepu, Carter, Nonu, C. Smith, Jane). It'll be interesting to see how they evolve and rejuvenate the team in the next few years.
The Boks have a pretty young team with some quality guys coming through, but still can't create much apart from setpieces and scrappy ball. Amazing strength in depth in the forwards though: several injured absentees, but no problem in finding replacements.
Finally, hard to write anything about Australia. They won 3 games while dealing a major injury crisis, so I guess that's good. But apart from some flashes here and there, they weren't very inspiring at all. Lots of people asking for the coach's head as well, so he'll be under severe pressure in the November Internationals in the NH, whether his players are back healthy or not.