It'll be fascinating to see how this game unfolds.
Ireland are deserved favorites and I expect them to win given their record in big games over the last two years. However I think one thing in Argentina's favor is most people would agree that the Southern Hemisphere teams look to be playing better rugby than the Northern teams so far. Over the last 6 months, Argentina have benefited from having played regularly against what currently look to be the best teams. They wont be overawed.
A lot has been said over the last couple of years about Argentina's ability to compete in the Rugby Championship. I think their progress has been impressive to be honest. That's not to downplay Argentina history before they joined SANZAR, but the Tri-nations (now RC) is surely one of the toughest international tournaments in world sport. They've won games against Oz and SA. They've challenged the All Blacks. They've beaten the Boks
in SA! It's not often the wallabies win in SA and I'd wager that Ireland would struggle to pick u a win over there.
I do subscribe to the theory that the higher the quality of your opponent, the quicker you improve. Of course we don't know which way the tournament will go from here, but it's looking like the South Hemisphere teams have the edge.
With all that said, as an Aussie I feel that Argentina is the better match up for us. We are familiar with how they play and we had their number when we played earlier in the year. Nevertheless, the Semi-Final I want to see is Ireland v Australia. From my point of view Ireland deserve to be in the Semi-Final given what they've achieved in recent years. Plus I think thats the game that most people want to see. Let's face it, if the Wallabies are going to win this thing, I want them to take out the Grand Slam on the way to the Finals!
....Of course Argentina v Scotland would be a good game too