It is slow but actually, I don't really mind it. I think it would be too ridiculous to have the group running away from walkers every week, it would kill any sense of suspense. With things as they are, I feel like anytime walkers make an appearance, then it is dangerous for everyone.
I can't determine if the people criticising the show are doing it because they have read the comics and are unhappy that the show isn't a literal translation of the source material or whether they are judging it as a standalone TV show without having that preconception. I've not read the comics yet (what am I doing?) and I think it's pretty good. I hate to admit it though, but the characters in that group are kind of unlikeable. I don't mind Rick, Glenn's really the only 'innocent' adult in there and Daryl is an American badass. But everyone else? Shane's definately an interesting character who I don't mind, but Lori, T-Dawg and Andrea are becoming increasingly unlikeable. And Sophia's mother just cries all the time and contributes nothing. I get her daughter is missing but really, that is the only thing defining that character. I don't even know her name!
I hate to make comparisons but at least Lost had likeable characters in there among the self-serving assholes. Maybe the group just needs to be expanded out a bit? Throw a few more characters in there and see what's up? Despite all of what I said, I still think it's a decent show, it's just not quite as good now as it once was. Well I think there's a mid-season finale after this one and it won't be back until Feb next year, so maybe they can sort something out til then? Maybe? Hopefully! I hear the finale is pretty revelatory though, apparently things won't be the same again, which could mean something to you comic readers.