So, saw it last night. I've only seen the original movie, and that was a long time ago, so I can't really comment on where the story diverged. HSpoon said they pulled elements from the manga and Stand Alone Complex to add to the story, so there's that.
It wasn't the best movie I've ever seen but it was ok. One thing I did really enjoy was the setting, it was beautiful and well-shot. The cinematography was really well done. It's the first live-action movie that actually looked very anime, which was kinda weird. I kinda feel about it like I feel about Andromeda. The settings were amazing and well put together, the story was ok. Just, ok. Not horrible, it was watchable and flowed ok, but there were odds and ends that felt out of place, mostly in the dialogue. Still, it's worth seeing for the visuals, but don't expect an awesome story telling experience.
Oh, and the do the camouflage really well, no floating head. And it was fun watching her in a physical fight while being invisible.