I liked the book more than the film. Neither ending were really all that great though to be honest. The book made some things a lot more clear, which they should have addressed in the film. For one thing, one of the downfalls of using the "signal" was that the longer it was the on, the easier it was for Skynet to track you.
The beginning with Marcus in prison was more dramatic and tense. And they also explained why there were hardly any machines inside Skynet, which would have helped that major story blunder.
Overall, read the book was good.