After the Masters, Bubba Watson was holding the trophy the American team was the strong favorite to win the Ryder Cup. The last couple of majors had been won by Americans and the Europeans had not really been making many waves. Since the U.S. Open, however, the tide has changed a bit and with resurgences from Euros such as Graeme McDowell and Rory McIlroy, I think the Europeans are now the favorite.
I think the home-field advantage of Medinah will certainly help the Americans, but the Europeans will have only one rookie that plays on the team, contrasting the Americans have three inside the top eight and may pick up another if U.S. Captain Davis Love III selects another with one of his four captain's picks. I do think Jason Dufner, Keegan Bradley, and Webb Simpson will play well, but they are rookies nonetheless and could easily get caught up in trying to play too well.
It seems almost a certainty that two of the four available captains picks for Davis Love III has have already been decided. By most accounts he will select Jim Furyk and Steve Stricker to the team. The remaining two picks are much more of a true unknown and adds some intrigue to the process.