The hardcover version of the book is about 300 pages long. It sticks pretty closely to what you see in the film (assuming you have seen the movie). It does have some additions that add to or expand what is in the movie, but they do not add anything all that substantive that radically changes the story shown in the movie. I do think the novel could have fleshed out a little more detail from the time jump between when Han gets off Cordelia and when he meets with the crew of smugglers. It did add some additional details from during that time period, but not a ton.
Overall, I think if you enjoyed the movie, you will enjoy the novel. If you hated the movie, there is not much about the novel that is likely to sway you off that point. I think it is a good story that flows well and makes for a fairly quick read.