Is the movie "Rosemary's Baby" a great horror movie? is it very scary? I have not seen it yet?

I just rented the movie "Rosemary's Baby", directed by Roman Polanski, in 1968, last night from Blockbuster, I am going to see it probably today or tomorrow when I have time. I have known and heard about this movie for a long time already, but I just never bothered to take the time to go see it. Anyway, is this movie really good? Is there a lot of blood and scary, tense scenes? Is it comparable with "The Exorcist"? I have already seen that one.