Again going back to my recent experience with the Sox announcers, they were asked whether the ball is juiced. Dave O'Brian said there's no doubt in his mind the ball is "different than it used to be".
According to O'B, MLB uses a different ball for the Home Run Derby than they do for games (no surprise) and "I wonder if they used the same balls for the World Series". I got the feeling he wasn't completely serious about that, but still.... He also said, "When Justin Verlander says that the balls are a little smaller and feel a little harder there's something going on".