I saw this last night and thought it was pretty good. I was a little apprehensive about it 1/4 the way through, but it picks up and eventually sucked me straight in. There are some fantastic horror movie moments in it near the end that had me glued to the screen.
It's very similar to Insidious, but I think Insidious' main antagonist is much better imagined and scary. Although saying that I do think The Conjuring is a much better put together horror movie. Almost like the director has refined his art. Its more thorough and better paced with non of the wacky characters that appear in Insidious half way through.