World war Z official trailer : the break down

Hey folks got you the World war Z trailer here i've read a few max brooks things, unfortunately world war z is not one of them though in the items i have read survival guide and the numerous stories one thing sticks out he uses slow zombies not fast ones.
Weather this is just a name only film or in world war z there actually fast zombies i dont know, i do know it looks reasonably decent. the new take of legions of undead rather than gangs mobs or hordes is the next step i think but a roiling wave of fast undead?
meh dont know about that, heres the trailer:

Reserving judgement for when i see it though could just turn into a white wash of bodies and with no substance, but i guess we'll see.