Just watched it this afternoon and I gotta say, I didn't like it.
I've intentionally avoided this thread so that nothing would be spoiled until I actually saw the film. To that end, anyone who reads the titles of this thread should be prepared for spoilers. So I don't think spoiler tags are necessary.
Going in, I was worried that this would just be another "Godzilla takes Manhattan" movie and that's exactly what it was, with a yuppie party tacked on at the beginning. The monster was okay looking. The scene of military attacking it from the perspective of a civilian hiding under a car was awesome, as was the Stealth Bomber run.
After skimming a couple dozen pages in this thread, I gotta say that I like the movie even less for trying to tell most of the story in internet marketing videos and websites. The shaky cam thing is over-kill for a full length movie, IMO. I know it was used for "realism" but if we're supposed to be seeing file footage then the movie should have been a collage of security cameras, cell-phone cams, professional news crews and the footage from this one particular camera. It would have gone a long way toward realism, with a lot less motion sickness.
The characters weren't engaging at all. We are meant to believe that a guy who was about to turn his back on everyone he knows in New York to go work in Japan suddenly decides to go into the path of devastation for a chick who showed up to his farewell party with another guy. I don't buy it. Maybe, if we saw early on that he's the hero type (perhaps by him saving someone in that first store they hide in), but that doesn't happen. They establish that the camera guy is a moron and love sick over a girl who doesn't know he's alive. This same girl suddenly goes out of her way to save his life and he doesn't even bother to put the camera down when she's being dragged away by the military? Again, I don't buy any of it.
Kudos to the people who made this movie, for breaking with convention and making something different. However, the execution was very flawed and generally left me unimpressed. I believe a movie is supposed to be so engaging that an audience can't look away for a moment. This film, forced me to look away and focus my attention on the reality of the theater, to avoid getting dizzy or nauseous.