Jurassic Park is my favorite movie ever, and has been for ages. I had wanted to read the book for forever, mainly since I had heard that it is rather different from the film. Having now read it I can happily say that it is not only different, but it's different in a very good way.
The book notably has a darker tone which, for me, works really well. The Story and characters also differ from their counterparts in the adaptation. Being the dino nerd I am, Alan Grant has always been my favourite character in the movie, and while he is different here, he remains my favourite. On the contrary, I've never been a fan of movie Ian Malcolm. (This is also the main reason why I don't really like the second movie as much, but I'll get into that on the Lost World page) The book version still is probably my least favourite character in the story, but I like him more here. People online tend to complain about the kids in the book, especially Lex, but I really liked them. And, like, their kids. Of course they won't always be reasonable. Let them be a little stupid. John Hammond is also notably different. In the book he is inarguably the bad guy and I enjoyed seeing that take. While the "spared no expense" line from the movie does not actually come up in the book, it would fit perfectly in an even more ironic way. Over all, all the movie characters apear here and are either notably different or are expanded upon compared to the film. We also get people in here that never show up in the movie, more insight into Biosyn and their shady work, details about InGen the movie doesn't mention, more info on the park itself and how it works and an expanded world which the dinos get to interact with.
While I'd say that the book lacks the wonder that the movie captures so well, it more than makes up for it with fun new dino encounters, and expanded world to learn about, way too many scientific details that show how well researched it is, and an over all really good reading experience.
As long as you can stomach two or three scenes with somewhat grafic descriptions this is an easy recommendation from me. I might actually like it better than the movie, and that says a lot.