I agree everything after Jerusalem things slid down hill... a bit, but hardly felt it was horrible. There were still some good moments there, particularly with the Jewish chick, the zombie version of William Fichtner and Pitt enjoying a cool, refreshing, Pepsi after getting his "camouflage" from the zombies. Overall, it's a movie I liked. (Saw it again this past weekend with another friend who wanted to see it.)
Plenty of mis-steps in it (zombie apocalypse and two guys are going for a rape in the dairy aisle?!) but overall I enjoyed it.
No, it wasn't horrible, it was stupid. It had probably already been said here, but the whole idea of infecting people with deadly but curable diseases for camouflage purposes is really really dumb. It's a terrible idea. What if one of those diseases gets out of hand and the world has a goddamn black plague or something in addition to zombie apocalypse?
It was also implied that zombies didn't bite one of the soldiers in South Korea because he was limping. The Israeli soldier girl had her arm cut off - why were the zombies reacting to her then, do zombies only bite the healthy people who can move easily? Why not send her to get the stuff at WHO, or at least to try to see what would happen if she got close to one of the zombies?
BTW, Segen in Hebrew is lieutenant, as in army rank, it made little sense not to give an Israeli girl a proper name even after the Jerusalem scene, but that's a minor nitpicking. It just looked weird to me.