I got one of those guest passes from a Kapikulu and played it for a bit with him and his team. In my brief hour of play I couldn't spot any negatives (but then again i only played for an hour).
From my limited experience, i'll give you my initial verdict in the form of "DayZ vs WarZ" where "+" means DayZ lacks the said feature and WarZ is strong in said feature.
+ A lot more smooth animations, not clunky and can actually jump over objects.
+ No hitting/bugging/random leg breaking through walls.
+ Easier interface, "E to pickup", not a somewhat broken 'G'.
+ Don't need to have special procedures to rearrange your backpack in fear of permnantley deleting an item.
+ Zombies move better, and aren't Usain bolt
+ Don't get stuck in doorways
+ Furniture/decor is to scale, and houses don't feel so claustrophobic.
+ Melee is a lot better/cleaner
+ Stamina bar
+ Zombies die instantly, upon death blow
+ Players die instantly, upon death blow