I must say the first half of the movie feels like it's a movie about the MUTOs. And, also, if the action sequences is what you are waiting you for sure have to wait. But trust me, it's so fucking amazing when they arrive. Atomic breath, the first time he uses it it's like a dream come true but the second time, oh lord it's fucking incredible. I won't spoil that because you just have to see it. A little hint, you might think of King Kong for a second just before he uses the atomic breath the second time. Also, I never thought he would use his tail in this movie. He uses it, one time. It was great
As I said before, the movie feels pretty weak when it starts but it feels balanced when it comes to the last hour. If you read bad reviews or comments about it being boring, it's because they take some time introducing the MUTOs and what they're causing. I feel that if they wouldn't take time to introduce the monsters the bad comments would be about that. They exist for a reason and everything else happens for a reason.
Overall, it's great. Watch it. Watch it many times if you can. I will.