I am not Swedish and I don't know the players that well, but DIF have Hysen back from an injury and I believe he is their best player (Rangers are after him). Both teams badly miss their star midfielders from the previous season (Fjortoft - Hammary, Andreas Johansson - DIF). Also, Hammarby won't have too many people cheering them on, because they will be playing on a small stadium instead of Rasunda.
Edit: There was an online chat with Lasse Sandlin (who I believe works for Sportsbladet) dedicated to this game.
http://www.aftonbladet.se/ettor/webb/26_normal.html
He reckons the game will end in a 2-2 draw.