It's an amusing gimmick book with a preachy message shoe-horned in. It reads as though Card wrote the basic story (the gimmicky part), then at some later date went back and wrote the preachy parts and just pasted them in between other paragraphs.
Like an earlier poster, the preachy message made me never want to read another Card book. But, the gimmick was pretty cool.
(Oh, and at least in the version I read, Card had this really whiny intro about how hard it is to be young and smart when all the cool kids hate you and you're smarter than your teachers and blah blah blah. Yawn. Spare us the geek-angst.)