Let me preface this by saying: I have never read the books.
This obviously impacts how I watch the show, and from the perspective of someone only vaguely familiar with the characters, this show is incredibly engaging and very well produced. If you are reading through reviews to decide whether the show is worth your while, please just watch it. I was hesitant at first too, and was pleasantly surprised.
I've noticed that most - if not all - negative reviews for this series are from fans of the books, because the series does not stay true to the original story. And while that is sometimes a valid excuse, I don't think they should be too quick to dismiss the show. For starters, as far as I'm aware, it was not intended to follow the books exactly, but rather loosely adapt them. Maybe one day there will be a screen adaptation that directly follow the books, but that is not this show. So treating it as a failed adaptation is unfair when it is supposed to be a separate story inspired by the books.
Because I'm not familiar with the novels, I am able to enjoy the show immensely (and I am eager to see where the second season takes it). So, if you haven't read the books you should watch the show. And if you have, please don't compare it to the books. Just enjoy it as it's own separate story, and you'll be blown away by the incredible acting and storyline.