I was looking forward to reading the book. In most cases where i both watched the movie and read the book, i preferred the latter. Personally i thought the move was pretty decent, so i had good hopes for the book (despite it being a bit on the thin side for me).
Right now i think i'm just over half way. The writer has used an unusual way of telling the story. You get small parts of the story from lots of different people who have been interviewed. So about every 5 pages you swap to a different person and get a whole different story. At first that really bothered me. Imo the story lacks a nice flow because of that. On the other hand it may just be an acquired taste. When i got about half way i did notice that it didn't bother me that much anymore. It's still not the way i would've written it, but at least i was getting more of a feel for the story.
And with all those short stories you have to really keep an eye open for the big picture. Because if you're not careful you tend to really zoom in on that persons part of the war and forget about how the big picture develops.
To sum it up: Is it a bad book? No. Not the greatest i've read by a long shot, but certainly not bad either if you can stand the way it's written. Would i recommand it? Also a no there. As i said, it's decent, but by no means great.
Since you seemed to like the movie less then i did, i think you may want to skip this as there's enough really good books out there.