Okay, I've had time to think about it, and looking over some Rottentomatoes.com reviews, I think I can use some quotes to express how I felt about it. ;D
The film presents some fairly adult themes in an understandable way, and it's also less cheesy and sentimental than a lot of animated fare. But it still packs in some exciting action sequences and impressive comic relief.
Well said. I figured that the rather serious situations that go on might be part of the reason this movie did seem to get as much flare as I'd expected it would: it might be seen as a little dark for kids, though I disagree. Kids need a little dark in their movies.
The emotional stuff is there, very present, but its also not in your face and overstressed as you'd see in most Disney movies (hey, I like Disney movies, but they just loooove to milk those sad scenes). I felt this gave it a greater effect, a more genuine feel.
The action was also cool, and the funny stuff was funny!
some of the voicework is bland, but it doesn't drag.
Unfortunately true, some of the voice-acting for side-characters wasn't top notch. Actually, when I think about it, Donald Sutherland's character is the one that comes to mind. But like Quinn said, it doesn't drag it down. Its like being a musician who can detect something wrong with a piece of music, but can only put his finger on it with reflection. Or if he's looking for it ahead of time.
While it isn't terribly original, and it seems to have a political agenda that may rankle some viewers, Astro Boy boasts enough visual thrills to please its target demographic.
-The Rottentomatoes Consensus
True, the values, or as this calls it, "political agenda", are not very original. Nonetheless I like to think of it as a movie that makes better use of those values than others have in the past. I'm not saying it does it better than all of them (I have no opinion on that particular), but certainly better than many.