I don't know much about what changes in this edition, but previous ones I haven't liked very much. It has some screwy targeting rules (if you fire into a space it hits friends first), maneuvering on the map is difficult, and the game discourages killing too quickly because as you level up, more zombies spawn. Also the game can take way too long, especially on some scenarios where you must find specific items in a large item deck. There are also larger zombies that you also must have specific items to kill (again, need to get lucky in item deck draws). Why they can't take partial damage, I don't know.
That said, I know I'm in the minority on this, because the game has done insanely well on Kickstarter and is well rated on BGG. And maybe the new edition is different enough to have fixed some of these things.
Classes Played: Barbarian (65 times), Monk (56), Ranger (33), Rogue (25), Cleric (21), Fighter (13), Druid (12), Paladin (11), Dwarf Fighter (10), Bard (7), Elf Wizard (2), Wizard (2)