DayZ is good, yes. But that is just an Arma 2 mod. DayZ Standalone should be out soon. But aye, I've played DayZ and it's fun, but I like Contagion a bit more.
i tried to get DayZ i did everything the video i watched said to do to install the things i needed but i just couldn't get it to work so i guess i'll take a look at Contagion