I'm aware of the many who think the film is dreadful. It does however have its admirers. I'm thinking particularly of a friend who works in film restoration who has a special fondness for Schifrin's score.
I liked the book better than the movie. The movie is unintentionally funny. This is a good thing or a bad thing depending how you see the film. The cast is great and so is the score. If you don't take horror films too seriously, I'd recommend it.