The movie vs. book conundrum continues

Brian and I went to the theater last night and saw Divergent. I wanted to see this movie because it looked super cool and exciting, and because Theo James is dreamy. But mainly because there can never be too many movies with strong female protagonists running the plot. So when those films come out, we owe it to the filmmakers who put their own faith in the story (as well as our own daughters), to put our money towards these box office numbers.
But here's my issue: I've got the book, Divergent, on my To-Be-Read Pile. I really liked the movie, and now I'm all scared that the book won't live up to my enjoyment of the movie. Or that something I read will shift how much I enjoyed the movie. I realize that this is opposite of how things usually roll, and perhaps if I read the book before seeing the movie, as I had intended, I'd feel let down by the film. But really, I liked the movie.
I haven't read much in the way of reviews of the movie from people who have read the book, so I'm not even sure how to deal with this predicament. Because if the movie and the book are similar in goodness, do I even bother reading the 400 pages that will be just as good as the movie, and therefore redundant in my head? Do I "waste" that time reading Divergent when I could/should be reading something else on my Pile? Or is it worth reading the first book, just so I can dive into the second and third book, and then not have to wait to find out what happens next?
A quandary!