I was super bored until we got into the second last part. Even then, I was a little bored. I still loved Rick Yancey's writing, though, so I had to give it at least 3 stars.
I think these books are really well done, I just have a hard time connecting with the characters and I find the world building to come at us all at once without warning.
I'll still be reading the 3rd book, just maybe with less enthusiasm.