There's a problem intrinsic within the movie. Most athletes are boring. Most high schoolers are uninteresting. You make a movie about the journey of 8 high school athletes? Odds are it's going to be uneven.
Why? Because the fact that a part of athletic training nowadays is putting on a public persona. I mean, look at Jerryd Bayless. His was a well-honed persona. He was on the whole time during the movie. And I say this not out of blame or scorn.
It's like Chuck Klosterman once said. We hate athletes with personality. It's what made Michael Beasley (who was the star of the film by far) seem unsafe enough that Derrick Rose went to a team that needed a low-post scroing threat. Conversely? If he gets his own blog? He could kill Gilbertology.
But I digress. If you're willing to let the expositionary period run it's course? The second half of the movie is pretty fun. And it is a worthy rental. Unless you like Cole Aldrich. He gets owned.