If what you would class as a scary film involves plenty of blood and guts then you really won't enjoy Paranormal Activity. However, if you enjoy super natural films then I recommend you give this a try.
I have to admit, there was a lot of 'hype' on this film, and when I watched it, it didn't scare me quite as much as I was expecting. But I wasn't dissapointed! The film, although fairly slow starting, was full of suspense and I think the story was quite interesting.
It is a low budget film, there is just one camera and no special effects...but for me, this made it believable. Also, the acting was good and much better than some of the unrealistic acting you sometimes see in horror films.
If you enjoyed the Blair Witch and the way it was filmed, I think you will enjoy this. I would say try and 'forget' all the hype that was made over this film before you watch...as lets face it every scary film that's released is meant to be the scariest yet and that usually isn't the case as people can make up their own mind when they've watched it!
The last thing I can say about this film, is it can really play on your mind afterwards!