I read it recently (based mostly on the advice of fellow Dopers), and I’m with JohnT - meh.
In the version I read, Card had a prologue up front where he noted that he was similar to Ender, in a way - recognized as very bright while he was still very young, what sort of isolation that prodigy-type categorization brought him, and how he spent his time dreaming how to write the book, being clever enough to think of things that others probably wouldn’t. However, rather than explaning anything or meaning anything to me, this prologue rather ruined the whole experience - I felt that the whole book, Card was yelling “Look at me! Look at what I can do!” And it was distracting. I felt like Peter Falk in the Princess Bride: “Yes, you’re very smart. Now shut up.”
The prologue led me to believe that Card wrote Ender’s Game when he was fairly young (not sure if that’s really true, or not), and I think it shows.
It’s an entertaining enough read, but it’s certainly not as good as I thought it was going to be.