I have read them all and I'm anxiously waiting for the next issue #94.
Personally, I prefer the graphic novels to the show. There's just so much more action. It's true the show at this point is doing it's own thing with the storyline but I don't think they could have done half of the things onscreen that are in the books. Could you imagine Carl shooting Shane back when they were outside of Atlanta? Will Rick get a hand chopped off? I doubt little Carl will ever get shot in the face on the show. There's plenty of harsh gritty events that happen in the books that more than likely never happen on the show.
The book's author has often said that no character is safe and he has held true to that tenfold. The show does a good job of filling in the gaps of the day to day stuff whereas the books, being a monthly release, skip over chunks of time.
Going by the books, the group leaves the farm and finds refuge in a prison. Things really hit the fan there but I can't see the show going in that direction.
As much as I prefer the books, I am looking forward to the show to start back up.