I loved this book. It's rare for me to read a book more than once, but I'm planning to read it a third time. What makes it work for me? I love the way Card has a clear idea about what a fight in microgravity would look like, how he keeps one step ahead of the reader and makes the concept of a battle school for children believable. But most of all, I like the story of Ender, his struggle and choices in an environment that would be hard for anyone, while he is only a child.
I liked the rest of the books in the series. Or more like, they were OK. But Ender's Game is special, different for the rest, and this is the one I find myself thinking about rather often. Just read it, you won't be disappointed.