It really boggles the mind how the 2 are even considered comparable. Granted Game of Thrones isn't necessarily brilliant, but compared to that piece of crap show, it's a work of art.
With The Walking Dead. the acting is god-awful. The writing, even worse. It's poorly conceived, poorly executed, and all around terrible. There's nothing happening, but people bitching at each other over and over again. People talk of how they believe things would go down if there was a real apocolypse of this sort, and to that, I say 2 things. First, lol no, the show is not realistic. Second, if this would be the reality, I would shoot myself right away, not because of the horrors of the zombies, or some utter BS about the twisted morals of the survivors around me. No, I would shoot myself because I couldn't deal having to hang with dipcraps like Rick, and his gang of dumbasses.
I stopped watching after the show after the mid-season finale of the second season told me that the events of the first half were a complete waste of time. I haven't wasted my time with it since. Although the topic of the show always seems to rear itself, and I don't mind taking the off opportunity to rant like this.
People will continue to compare them, but as far as quality goes, they are so far at the opposite ends of the scale with which to measure currently airing TV shows.