The girlfriend and I just got back a little while ago from seeing Cloverfield and, this being a horror blog among other things, I thought I would give my impressions of the film (along with probably half the blogosphere).
In a word: excellent! For those who have been covering their ears and screeching, "La la la la la la!" for the past two months, Cloverfield is the first-person tale of several people who happen to be in New York City the night a skyscraper-sized monster attacks the city. The movie is essentially a "Blair Witch Godzilla", told in brief camcorder clips.
This is not a movie which gives many answers, which is as it should be. The best horror films 'hold their cards' close to their chest, and give away secrets only sparingly and for maximum effect. The intentional incompetence of the cameraman keeps a clear view of the beastie from the audience for quite some time, offering only disturbing hints of what has truly descended upon the city. The best comparison is the appearance of the alien in Alien. Never fear, though: you'll get a good look by the end.
But this film isn't supposed to be about answers: it's about experiencing a completely incomprehensible and overwhelming terror from the victim's point of view. In that, I found it nearly perfect, and am already considering a second viewing (something I haven't done in years). There are a number of nice little touches, and secrets tied to the viral marketing, that would make such a return rewarding.
There is very little opportunity to learn about the characters, but the film uses a very clever conceit to give us just enough background to care.
In conclusion, Cloverfield is an excellent, quick-paced horror film that tells a scary story and delivers pretty much everything that it promises. And the girlfriend liked it too!