I honestly thought this would be childish and corny without much of a plot, but this proved untrue in the first half of the movie where a very serious plot grew unexpectedly. Sure, some of it was goofy, but it was really enjoyable. I can't regret it and I'd see it again.
I'm actually getting sick of Marvel making new supers just to milk it. Shazam was quite a good story to compete with. More believable than some hippy with a magic hammer anyway.