The US most probably isn't going to get to the quarters.
That said, both teams feature iffy defenses, but Argentina's has held up better... though against lesser talent.
I would actually give the midfield edge to the US... especially if Michael Bradley can snap out of whatever funk he's in.
But there's no question which team has the better forwards. Though I'd like to think that the US would never let Messi cut left... meaning that one of the other strikers would ultimately score the winning goal. The 2nd Iranian defender (midfielder probably) on the winning goal should have absolutely stepped up earlier and then run into Messi when he cut left. Give them a free kick from that point with a wall, but don't stand back and leave your striker alone to defend Messi one-v-one as he sets the ball up on his left foot. That was HORRIBLE defending. Even worse than Beasley not closing in on Cristiano Ronaldo bad.