The comic is still ongoing and a few more numbers will still appear, so time to stop for a while :)
Without entering into spoilers, I will only say that the comic is quite good. As I commented with the first book, it focuses a lot on the psychological aspect and human behavior in a supposed apocalyptic global zombie outbreak, and this volumes make it even more important.
How would people survive on a long term? Will they become crazy? could they adapt and survive? and how? How the main character can protect his family at all costs?
This are just but a few points the book tries to tell. There are some typical movie scenarios too, but either as another situations or more in depth.
The plot has twists, some predictable, others a complete surprise, and in the fourth book there is a sudden but welcome pump of action and changes that has left me hungry for more.
I've noticed some coincidences with the book World War Z, but again, being a long-term series, The Walking Dead goes deeper and gives much more detail.
Highly recommended, specially now that it is back into Amazon stores (book 2 was almost impossible to obtain until recently).