Simply, Awseome
1: Kick ass Justu. All my top 5 favorite justus are in this game. With Rasengan being no. 1 and Chidori being no. 2 of course.
2: Cool Stages. Most of Kohona is in this game. From the Ichiraku Ramen Bar to The Final Valley. And of course you can break stuff on the levels.
3: Butt kicking Characters. All of the Kohona 12 are in this game. Including their sensis, the Sand Siblings, The first 2 Akatsuki members, Rouge Ninja from the Hidden Mist Village, Orochimaru, Kabuto and The Sound Ninja 5.
4: Fun RPG mode. Fighting in an all out brawl against Jonin for an new law, Sign Me Up!
5: The Heros History. Of course it would'nt be much fun without playing the story. You pretty much play the defining moments in the story, From Naruto's graduation from the academy, to his climatic battle with Sauske.
Thats why I think Naruto Ultimate Ninja 3 kicks ass.