Well I've seen the movie twice, and I followed the marketing campaign and the websites for the film since opening day of Transformers. I was not disappointed in Cloverfield.
There are some key points to keep in mind:
- It's produced by J.J. Abrams, so you should go into it knowing that you're going to probably come out with more questions than answers.
- It's a monster movie, nothing more, nothing less. If you expect a huge drama of character development mixed with a giant monster mixed with an action hero, you will sorely be disappointed. If you expect to see a group of people evading a giant monster that is destroying NYC and trying to survive, then you're on the right track.
- If you're motion sensitive, you may want to avoid this movie (even though I can't recommend it enough), or try and take motion sickness medicine like Dramamine.
- If you find yourself unable to suspend belief for a little while, you will be disappointed. Yes, this movie is supposed to be filmed with a home camera, yes the camera falls, gets crushed, etc. several times throughout the movie, and yet it still seems to be fine. People just love to criticize the movie on points like this, but you just need to be able to say screw it, and realize that if the camera broke, that would obviously mean the movie would end, and that wouldn't be very fun.
- The movie was created to stand completely on it's own, with no relation to the marketing campaign online. The movie doesn't utter the words "Tagruato", "Jamie", "Teddy", "Slusho", "TidoWave", "Chuai", or "Ganu" once. Nothing you've seen online is apparently referenced in the film (save for a Slusho T-shirt). As the director Matt Reeves said, the online stuff is a prism for looking at the film once you've seen it --- meaning that you can use what you've learned online to attempt to come up with answers to the many questions the movie leaves you with.
Overall, I loved the movie. It does exactly what it sets out to do --- put you in the shoes of struggling survivors of a monster attack while they try and escape, help each other, and so on.