I saw it today and thought it was a well-made, technically proficient movie with many good moments and sequences. But it was also often very boring.
Probably the biggest problem for me is that the movie takes itself far too seriously. There is next to no humor in it, and it never develops a sense of fun. Now, this is not necessarily a bad thing, as the original 1954 "Gojira" was also a pretty serious affair, but that movie actually had something serious to say about the nuclear destruction of Japan in WWII and the morality of weapons of mass destruction. This new Godzilla sort of nods its head at Fukushima and environmental disasters, but doesn't really seem to have an opinion about those things. So in the end, it's just a fairly slight movie about giant monsters smashing stuff, and as such probably shouldn't be so afraid to have a bit of fun. Oh, and maybe use some colors other than grey and brown?
Part of the problem with the general reaction to a Godzilla movie is that it would be some cheesy monster movie. But this one was meant to invoke the spirit of the original movie. I think had the script not been a serious one you not have had so many good actors in the movie.