It's just OK. I've really liked the first 2 seasons, because it was realistic and gritty, but I got so bored after them and couldn't get past season 4.
In the first couple of seasons, the priorities are obvious and make sense. The characters (Except maybe John Bernthal, he was great) were never well written, but they were believable. It was clear what was going on, who everyone was and what everyone was like, and on top of that, there was the constant threat of zombies.
After season 2, the zombies basically made no difference to the show. All of the new characters were boring and forgettable, or just added nothing. The goals went from Food, Shelter and Health to who was sleeping with who, and they had to remind us that zombies exist every 2 or 3 episodes. It just got really dry, and went from a horror/survival Drama to a Drama.
I'd give the first couple of seasons a try, but I'm not going to bother going further. Not worth it