I saw Cloverfield yesterday afternoon, early enough so I could avoid a theater filled with douchebags. I understand that this was a good thing, because people I know who saw it at night with the aforementioned douchebags were so annoyed by them, and so pulled out of the movie by them, it seriously fucked with their ability to enjoy the film.
If you haven't seen it, I recommend it. I gave it 3 out of 5, but only because the first-person shaky camera stuff made me violently seasick, causing me to look away from the screen more frequently than I did with Blair Witch (a movie, by the way, that I enjoyed as much as "meh" can be enjoyed, and which doesn't deserve to be compared to Cloverfield, IMHO.) On story and effectiveness, I give it a 4.6 out of 5but the camera stuff really messed with me, and I suspect it will mess with other viewers, as well.
Assume there will be spoilers in comments, because I'm starting the comments off with my extended commentary on the film, which you should not read if you haven't seen it yet.
The Bad Astronomer (who I owned in a Techonobabbloff yesterday) has some nitpicks and a review that I agreed with pretty much all the way, too.