I agree with others that major parts of the book were left out; however, for those who are not readers of the book, the movie will help to advance the storyline sufficiently that you'll be ready for the next movie. It was still very good such that 2 1/2 hours went by very quickly!
I originally purchased the A&D book about 10 years ago and it had basically the same storyline and ending that is shown in the movie. I purchased a newer version of the book about a month ago and the new book had a different ending. Haven't a clue why the book was changed. But if you read the recent publication of the book, you'll go out of the theater thinking the movie wasn't true to the book...it was, but it was the original version. I heard many people comment on this when the movie was over. The best thing about this movie is that it is historically accurate, which makes it all that much more enjoyable.
Each time they bring out one of these movies, they fill in another piece of the overall John Connor story - this movie is no exception. That being said, though, it is a very small piece with a larger and different storyline attached, which is very interesting. Being a PG13 instead of R, it meant less gore or bad language, which I personally appreciated, and more story. Well acted. The choice is in whole stars, but I would actually give it a 3 1/2.
They took a very simple storyline and added a lot of Hollywood effects, but the overall movie ended up being excellent. I gave it a 4 instead of a 5 because they tried a little too hard to bring in known characteristics of the characters' personalities that felt staged. As an example, Spock sits in a chair that then rotates in place and he says "fascinating." For Spock to say that about something that was absurdly simple, it just didn't fit the defined personality of the character. Would I see it again anyways? You bet...maybe even 3 or 4 more times! It was a great movie and even though it was labeled PG13, the 9-12 year old group will love it and parents will find almost nothing offensive for them.
Not as good as the other Indiana Jones movies, but definitely holds your interest. The first three had a better and tighter storyline. This one was a little weaker, but good none the less.