I'll admit, I'm actually looking forward to it. While I didn't necessarily love PARANORMAL ACTIVITY 2, I would still rather sit down and watch one of the PA films than any of the SAW sequels (mind you, I said sequels, since I quite enjoyed the first SAW film). When PA:3 was released, I was sure it was going to be horrible -- and although the ending was bad, the rest of the film was pretty damn tense. I like the creativity of them, and the pacing: they establish a formula; an expectation, and yet still manage to find an inventive way to present the material (in PA:3, they introduced the oscillating camera, which I thought was employed really effectively).
I don't know what all they have planned for the next film, but they were smart to leave enough questions unanswered, thus making room for another sequel. And while I'm not expecting it to be groundbreaking, I'm certain it will at the very least be entertaining, which is why I'm looking forward to it.