I just finished this and wow, it is definitely as good as Enders Game.
I was at first very wary of reading this. People had said it was vastly different from Enders Game, which it was, but I battled on, mainly because I love OSC's writing.
Although vastly different, Ender's character is just as good. His journey is almost inspirational, even though he was the cause of the Xenocide.
I did find it slightly confusing at times, especially with all the Portuguese wrapped into it. Yet once you got past half way, it truly blossomed into an amazing, philosophical book about what we consider 'human'.
I will definitely continue with the rest of the series.