The novels and films work on a dinstinctly separate kind of story-telling.
The novels are dark, gritty, and extremely scientific - and their goal is not the story alone, but the message and thought around it. One of the things I like about the Crichton Literature is that Crichton almost never looses the possibility to enter up a scientifical speculation or reflection, or even historical notes (in Congo, hiyo, they helped me with Geography). He always gets up an excuse to talk about things along these lines, and I love that. The characters in the novels are also darker, they swear a whole lot more, some are even more 'mature' (Tim can't get his eyes off the legs of Ellie Sattler, for example), and the dialogues are way longer and more in depth.
The movies work on a kind-of different plan of storytelling. They tell a classic Sci-Fi story biased on spectacle and fable, rather than exploring down to the last detail the theme they revolve around - like the novels -. Don't get me wrong, I'm not saying it's a bad thing.
But I love both the novels and films - in different ways.