I enjoyed this movie. It basically worked as advertised - a light summer romp with comic book themes and stuff blowing up. It's a little odd in that it takes the Fantastic Four a good while to knock it into their heads that saving the world is job #1, but they get there. I do like how they played up the "celebrity" aspect of the FF as compared to the dual lives of a lot of other superheroes (they don't have secret identities and are headquartered right in middle of New York).
And of course there's Jessica Alba. Jessica Alba on a giant movie screen - every lad in America should have that prize. The funny thing is that there's more nudity of Jessica Alba (implied, but still, nude) in this PG rated film than in her role as a stripper in Sin City which was rated R. I do get a little creeped out at the romance between her and Ioan Gruffudd (Mr. Fantastic) because he looks more like her dad than the love of her life. But fear not, Jessica Alba wears glasses for a quick bit in this movie and all is well.
The movie could have been a bit longer, frankly, and the third act feels rushed. Solid popcorn fun.