I played it for a few weeks. I understand it's an alpha, but a good portion of my experience was rather frustrating.
There were several times I'd log in, and before I could even connect to the server, someone (whether or a zombie or person) had killed me.
There's a lot of bad glitches that cause zombies to walk through walls. On the worst occasions, I'd enter a hallway where, for some reason, the hallway was not wide enough to do a 180, so I'd have to die because I couldn't aim at the zombie behind.
The blood system can be a real pain in the ass. Realism is cool. Having your character fall on the floor every 7 seconds and the screen go blurry every 2 seconds is unplayable. Anything under a certain threshold of blood is a death sentence. And considering I played with a friend of mine, every death meant another 30-40 minutes of trying to meet up again.
I'm interested to see where it goes, but I think I'm going to wait until it gets moved to ARMA 3. It's certainly a cool concept.