I really enjoyed this movie, and I think a big part of the reason is the way it was marketed. There was a lot of mystery, they showed you a decapitated Statue of Liberty on the movie poster, they showed us people running terrified in the streets, but they were careful not to show you what was causing all of this horror. This sparked my curiosity to the point where I just had to see this film, and I was glad I did.
One of the great things about this movie (in my opinion) is the fact that it is made to look like it was filmed with a hand-held camcorder. It has a "home movie" feel to it and that makes the events depicted seem more real.
This film is short and sweet (about 1hr. 15min.) so it doesn't drag on like a lot of movies. I really delivers in the action department. The special effects are well done, the Statue of Liberty gets mangled (as you know), and the Brooklyn Bridge gets destroyed (along with countless other NYC structures), and then there is the monster, which almost looks like a... Okay, I am not going say what the monster looks like, because that would spoil the fun, but it is interesting when it is finally revealed. It leaves you thinking at the end, and that is all I want to say, because I don't want to write a spoiler here :)
If you are looking for a movie with some deep and meaningful or romantic plot, go buy something else. Basiclly, Cloverfield is an entertaining and fun monster movie. If you are into this kind of movie, you have to check this one out!