Enjoyment of Cloverfield is completely dependent on the willingness of its audience to embrace the format in which it is presented. Actually, "embrace" might be too lofty a goal, perhaps "accept" is the more appropriate word. Or no, "forgive" would be an even more realistic expectation. If you can forgive the inconveniences and limitations of Cloverfield's format-- that is, being shot from the point of view of a handheld camera-- and if you can appreciate the unique dimension it adds, then you can enjoy the movie.
That said, it's completely possible (and even understandable) that a large portion of the audience will just be unwilling to accept the movie. The person in front of me at the ticket counter line was a middle aged woman who was asked by the cashier if she was familiar with the Blair Witch Project (a movie I have not seen, by the way), because Cloverfield is that kind of movie, and a lot of others had been complaining about it.
The camera is as unsteady as you would expect from a cheap camera held by an amateur while New York City is attacked by a monster. At one point, following a helicopter crash, the camera lays idle in the wreckage focusing on nothing in particular. And it stays idle for quite a while. By this point the audience has so completely resigned to the reality that the viewpoint can not and will not focus on what you want it to, that you will start to consider the possibility that the camera will be laying idle for several minutes.
One one hand I'm tempted to give a high score for the innovation and sheer audacity of presenting a monster movie this way. On the other hand I'd have to take away points for the natural annoyances that the format imposes. Overall, thumbs up.
The movie ends in an explosion that makes it unmistakable that the last two surviving characters have died. Keeping as true as possible to the style of the movie, the low key end credits are displayed on a backdrop of blackness, over complete silence. At that point the audience starts looking around awkwardly, wondering in silence if the movie is done. What followed was an extremely disconcerting walk out of the movie theater. Though it would have broken the consistency of style, I really would have preferred to hear music over the end credits. That would have taken a big step towards convincing people that what they just saw was a movie, not merely an exercise in patience.