I really want this game but its rated mature and im only 15. What do you guys think? Anything really bad about it?

Noooo...not at all dude. There's some mild cursing as well as some sexual and violent themes. However since this is a cartoony game it's nothing too graphic. Besides, I was 15 when I got this game almost a year ago.

Oh great thanks. The rating makes it sound so much more worse, but it looks awesome.

It's is my favorite game of all time. Go buy it.

I've got the european version, which is rated 16+.
There are some content descriptors on the back, which are violence (which is really pretty minimal), and drugs (whihc in this game is just tobacco and alcohol), and of course there's swearing.
It really doesn't deserve the rating it gets, but because America is a christian nation (and the european ratings board tend to follow the amercans' lead), it is rated as it is. I'll explain this point further, if you like, but it would include some spoilers.

Pole-dancer/stripper Shadow and boss.

quote Lady_Sparda

Pole-dancer/stripper Shadow and boss.

Partly.
But mostly it's Kanji.
The ESRB are terrified of having hoards of angry christian parents rising up against them, saying this game puts thoughts of homosexuality into their innocent children's heads, or something equally crazy. So to cover themselves for this, the ESRB made sure it was rated so that children couldn't play it.

if you are somehow able to buy it, you should.

I didn't really find anything offensive in it. There wasn't really anything over the top in it except what was mentioned above, but that is no big deal.

I was reading an artice in I think the New Yorker about how Persona 3 was what was wrong with the video game industry and that it promoted suicide (in reference of course to the SEES members shooting themselves in the head.). The article seemed a little over the top, w/e.

Any article in any form of media that says games promote any particualr kind of behaviour should never be believed.
The only people who would be influenced in any way at all by any games are people that are either too young to be playing them, in which case they shouldn't be playing them, it is the shop/parent's fault, not the game's; or people who are mentally unstable, in which case they should've been diagnosed sooner, again not the game's fault.
Remember: we all fear what we do not understand.
The media simply like to use games as a scapegoat because they are an easy target, and bad news always sells beter than good news.