Not having read the book and only interested in movies like that for their entertainment value, I'm looking forward to seeing WWZ. I expect only mindless action and mayhem from this, so don't see how I could be too disappointed unless the plot directly contradicts itself.
That's the thing that kills some movies that could have been good for me. Things like - at the beginning of the movie the aliens move super fast, employ great tactics, and are unbeatable but by the end of the movie they're slow moving and dimwitted. I can think of one movie I still like in spite of that but it would've been so much better with some consistency.