Well... it depends on what the reference is, one of the three series or the manga?
I think the animation was fabulous in the 2003 series (not that it matters since the movie will be in 3D), but the scenario in some episodes left a bit to be desired. I thought Astro was a robot first and a boy second, while it should be the othe way around. Tenma was turned into a wonderful character however.
I discovered Astro through the 1980 series so that one will always remain my favorite. I'm not impartial.

However I doubt the movie will take much from it, the only interesting story going from one episode to the next was the one involving Atlas, and I'd rather have something new for the movie.