I've gotten all the trades so far and I agree that initially it was just random stories about survivors and trying to shock people. I think there's 2 crossed series going on with one still being random stories but the main one that takes place in Scotland is good.
I remember the first trade I picked up all those years ago. The uber nerd behind the counter told me that it was so gory and violent that it actually made him throw up. I'll admit that as comics go, this one takes the cake for ultra violence but not once have I even felt revolted. Maybe it's all the horror flicks I watched as a kid/teenager that desensitized me.