Ultimate Ninja Storm 2 is a well packed game with impressive quality (graphics, animation, sound) and decent gameplay depth it only has some dificulty curve issues though, with some quite ANNOYING bosses beating the shit out of you even on beginner mode
You can pass on the first it has about same quality with the first bunch of chars before shippuden, but a badly done and boooring story mode in a lifeless konoha.. jump all over the same small map grabbing some scrolls all the time between missions.. meh
I suggest to buy the 2nd if you find it at a decent price, if not then wait for the upcoming sequel which will improve on the same formula, as i read it will combine chars from games 1 & 2 + updating to most recent shippuden era
I'm not a big Naruto fan so here you get my gamer opinion ^^