I have played only a couple of Zed Or Alive confrontations (that's how the games in Zed Or Alive are called) and I have to say that IS a survival game and CAN create an awesome atmosphere for the players in either side of survival (either humans or the virus)! I highly recommend it but I also have to make some complains! What I found the game to lack is:
-Skill trees/tables/charts. So when one of my characters leveled up and I rolled the dice it came up to take a new skill BUT... what skill? what kind of skill? I don't know what skills the game have and support!
-Only 3 "races" (for humans) and I say only because it keeps the game pretty "low on choices" for warband creation! (Although it has an awesome range of equipment and weapons!)
-Complete point system (it has a point system but!), doesn't have point values for virus player! And it doesn't specify starting points and mean play time for specific points! (I am not a competitive tournament player but I really like well balanced (themed) games!)
BUT if you can find ways to overcome these "drawbacks" of the game and especialy the first (if you find a way please let me know!), I can't recommend it enough! It has an awesome campaign system and it makes you believe that the creators thought about EVERYTHINK! It even has a survival (hunger, thirst) system! Vehicules are hard to find, and really expensive to maintain! Although I find it pretty hard for a character to DIE and get out of the roster, injuries are really common and easy to acquire them! Your warband will have a base that gives you some advantages depending on what it is (from an old garage to jails and police stations!)... The dice mechanics are pretty good and easy to learn! The second game found me (I play mostly solo!!!) to just check the rules only 3-4 times! A lot of equipment and weapons to choose from!
The game is a really good one and I highly recommend it for its deep zombie/survival feeling and its awesome story-telling capabilities!