Thanks to bfw182 for his awesome evaluation notes!
Naruto ( No.1 Maverick )
Naruto has recently became a much better character in the game due to the newly added feature Limit Break.
At level 100 he has 1226 HP and 1047 ATK but when he reaches his new max level of 150 due to the Limit Break he has over 2000 HP and 1600 ATK.
His Ninjutsu and Secret technique also are not to expensive in Chakra costs being 4 for his Ninjutsu and 8 for his Secret. Both of these attacks also have good damage multipliers so he can do a massive amount of damage but unfortunately only to a single unit.
He has a high boosting damage Buddy skill if he isn't needed to be active for the mission you are playing and he also has a damage increasing Field skill if you need to hit harder. As with most 6*'s he would be recommended.