One of the big things in publishing today, is the young adult novels. Harry Potter, and the Twilight series are examples of the young adult novel which should give you some idea of the range. "I am Number Four," falls straight down the middle between the two. Basically, those that read the books will like it, and those that didn't should be amused enough to not feel cheated.
It's the story of a young teen growing into manhood. Being an alien, manhood means having flashlight fingers. But it is not all cool, see he's near the last of his race and the aliens responsible are hunting him and the others with special powers. Protected by an old warrior and a puppy, they are constantly on the run and changing identities. In his new school he actually finds a friend and a girl, and so he doesn't want to keep running. So it eventually becomes a showdown between him and evil aliens. Everyone helps out with and there's a mysterious girl who shows up who also has powers.
I like the bad guys. They aren't deep or anything but they are mean and at the same time goofy. They have tattoos and funky noses and sound like steroid cases with a bad cold. They have no redeeming features and so it's great fun to see them get schooled. The teens act about as well as can be expected. The plot keeps moving. The special effects are ok. Like I said, fairly painless.