As it often happens I saw the movie before I read the book. And I think that they both are excellent. Later I had to read "Wuthering Heights" by Emily Brontë for my literature classes, and I think that it is one of the best books I have ever read :)
It is a love story and a hate story all at the same time. Lives of the characters are so mixed up that sometimes it is impossible to imagine that the story could go any other way.
Catherine and Heathcliff love each other and seem to be one person, but somehow they decide that they are not to be together. Catherine is too proud to be with a poor man, and Heathcliff overhears a wrong conversation. They fell apart but when Heathcliff comes back, althout married, Catherine behaves like she still loves him. That changes everything and everyone's lives.
The story is grasping from the beginning till the end. It is complicated, raw, full of emotions and secrets. I don't know what makes the story so great, but is sure stays with you for a long time.
P.S. And watch the movie!!!