just some observations from the test,
i had 170ms connecting to a server from Croatia. Despite relatively high ping fighting zombies had tight feeling, i havnt experienced rubber banding, or zombies teleportation around or other manifestations of high ping. There was however 3-4 occurrences of zombies disappearing during the fight, in one occasion zombie bit me before disappearing but i had no negative health status.
When i just joined, game seemed to be faster than i remember it being from SP, as if it was fast forwarded, not sure if my mind was playing tricks on me or was it due to lag or something.
Reading skill books seemed way to fast.
Near riverside logging/construction area during the night, it just arbitrarily cuts off to black where the north wooden fence is, maybe putting some outline of the fence would be better.
All in all i havnt experienced any game breaking bugs while i focused mostly on fighting zombies.