I would only recommend this book to people who have already seen the movie. The book obviously does not capture the epicness of the movie.
I am obsessed with Pacific Rim. Obsessed. It is not my kind of movie at all: action adventure with a predominantly male cast. Alas, I love it.
The actual writing of this book was basic. I imagine it's hard to take a script and try to write a book around it, especially a story of this caliber. These kind of characters are better in the flesh than on the page.
Nevertheless, the book gave me some better understanding of the characters and of the Jaeger program and its history. So, it was worth it.