I have to agree with Galva. I'm not normally a fan of giant monster movies, nor do I have a great love of shaky cam (HATED Blair Witch), but watching this movie in the theater really made me feel like this was the best film of it's type that I'd seen. I think it taps into the fun memories I had of going to Universal Studios and Disney/MGM Studios. The first person perspective really made it feel like a ride sometimes. It's one thing to have lots of "God's eye view" shots of the monster stomping on ant sized people, it's more interesting when you see this stuff coming at you in a few scenes.
The trailer was great because it showed you enough to get your attention, and then it didn't tell you hardly anything else about the movie. I hate a lot of movie trailers these days because they give you way too much information. Some of them tell you almost everything that happens in the movie except for the ending, and you can pretty much figure that part out based on the tone of the trailer and everything else you were presented with.
I also like that we didn't always see the monster because the film was really more about the crisis it creates for the characters rather than what it looks like, it's origin story, or it's motivation. That's why I'm a little confused when people say they were "disappointed" by the look of the monster. Sometimes it feels like a McGuffin, so would it really be more effective if it were designed differently? I actually thought it looked pretty original. When some people asked me what it looked like I said, "Well, I don't really know what to compare it to, but it looks pretty messed up."
I also like the fact that the first 20 minutes or so of the film don't really give any hints about the monster attack at all, save for the ominous title card at the beginning of the film. A friend of mine told me he got so into the plot at the beginning, that he almost forgot it was a monster film.
Incidentally, I didn't get the seasick feeling some people got from the shaky cam. As long as they don't start physically moving the seats during these scenes, I'm good to go. Normally I'd say the movie is best viewed on the biggest screen you have access to, but if it's really a problem for you, just watch it on a normal TV screen / computer monitor and you should be fine.