It starts off fun and neat, but as the movies go along it gets pretty dark and mature, all kinds of twists and turns and people dying and big huge wizard battles and stuff, it's actually a really well done series because they start off as kids so the theme sort of reflects that, then as they age through the movies the movies age with them and it gets more mature and deep. You won't be disappointed if you start watching them from the start and keep with it.
Yeah I know a few people that have seen it and really enjoyed it. Not even people that read the books and got into at a young age like so many did. But people my age that saw them later on that still enjoyed it. I could tell that the later movies got more mature. I remember people wondering if Harry would die in the final movie.