The storyline was actually a little different than what I expected, but in a good way. I won't say anymore so I don't become one of those people I loathe, you know, the ones who reveal too much of the plot, forever ruining movies you have yet to see.
I will say this though: if not for the storyline and the acting, go see Step Up 3D for the dancing. It will really blow you away. This is one of the rare movies that's actually shot in 3D. When the dancers perform you really feel like you're part of the action. I even had to restrain myself from high-fiving Madd Chadd whenever he extended his arms. (I'm serious here.)
Last week some of the Step Up 3D dancers were on Late Night with Jimmy Fallon to give everyone a little taste of the top notch performances in the movie. If this doesn't convince you to see it, I don't know what will. (Perhaps a robot high five from Chadd?)