When our group gets the duels going, it's actually a fun experience spectating the duel in progress. This is different from the other games, including Magic, where if you aren't in the game, you find something else to do (deckbuilding, etc.).
I personally enjoy watching the game as I feel the open spellbook concept really makes it seem more of a "real" match than a MtG duel. While I know what each player can do potentially in either game, knowing that the players aren't limited to a random draw to act/react makes all the difference for me in spectating. Well, in playing too...
