The characters are all interesting people... 3-dimensional and dynamic. Without getting into spoilers, it was obvious to me what Alaska's "secret" was, although knowing that didn't lead me to any answers any better than the Colonel or Pudge. I really liked this story... the characters, the plot, the writing. The teens were realistic--being away from home in a boarding school they behaved more like freshmen at college--complete with all the risky behaviors that teens away from home for the first time get involved in. Nothing was gratuitous... it all made sense for the plot and for the characters.
It's definitely a high school book, not a middle school book, but should appeal to boys as much as girls.
Reading: Gifts--Ursula K. Le Guin
On My Nightstand: baby poop books, as usual.