I have some mixed feelings toward Ender's Game thus far (about half-way). There are a lot of things I like about it, but a few things that I don't.
The characters in Orson Scott Card's premiere novel are incredibly designed. They're compelling and exceedingly clever. That's also a downfall. They're too smart. I don't care if these children were made in a lab, Card bends the golden rule of science-fiction "it has to be plausible", not in the technology or setting, but in character. Granted, the characters are only as smart as Card himself. That, however, is a plus, he's very intelligent.
I've never encountered the point-of-view style found in Ender's Game. It's neither a positive nor a negative attribute. Third-person limited seems to be the POV, although statements break in in the first-person occasionally. Thoughts with a flourish? Perhaps.
While I consider this book "adult" for the purpose of my "currently-reading" list, I'm not really sure on that. It's violent for sure, although not sickeningly so. The main character is a child young enough to be a chapter book protagonist, further complicating the audience. The prose has a few too many "tells" and reads at a far lower level than The Wheel of Time, poking at young adult. I'm sure I could find Card himself explaining the audience if I looked hard enough, but I'd rather continue speculating, at least for the time being.
Overall, I'm excited about Ender's Game and the rest of the series. It's a change for me, a necessary change if I want to become an editor of speculative fiction, taking with open arms. I might leave further comments when I finish.