Firstly, I wouldn't bother seeing in 3D as you probably won't notice, I think this is a conversion,and because its an action movie, you won't have time to see any parallax of 3D.
While the movie is perhaps a tad too long, it's an exhilarating ride, and well, we just want to see a zombie film right? What strikes me is the rating in NZ. There is very little liquid gore or blood shown- so the light stomach'd can just worry about getting a scare- and scare they will! These are sprinting zombies- so very scary. There are some interesting studies into rat swarms for the massive simulations of zombies- incredible Vfx technology! A lot of wide shots on various locations make this film quite spectacular visually. Haven't read the book, so for full blown fans I'm not sure how much it sticks to the books plot. Totally worth a watch for the zombie swarms.