We got into Game of Thrones this past weekend and really have enjoyed the series. I'm not familiar with Martin's books, though I'm thinking I'd like to go back and get into them if the world-building and characterization are as keen as in the television series.
It's not a perfect series, mind you, but it's wholly engrossing and nicely shot. The visuals are fantastic (love those shots of the wall) and the sets are beautiful in their own right. The costuming and score complement the dark tones--all quite nicely foregrounded by the compelling opening credits sequence. If you've seen a few episodes, you'll notice that it's got it's own cinematic signature. If you just walked in on an episode and you've seen it before, you'd know what you were seeing pretty quickly.
The negatives are also due in part to cosmetics. These stars, even the fierce Khal Drogo, have perfect teeth and flawless skin. These people (excepting Ned, of course) just don't know much about rough living, and that seems not to jive with some of the stuff I've read about Martin's books (there is a crazy in-depth Game of Thrones wiki online). Some of the characters are better developed than others, and that uneven treatment is a bit distracting. But still, I'm just in the first season. I'm sure some of the folks that haven't been touched on much will come into fuller dimension down the road.
All in all, it's been fun to get into a new world with a bit of a horrific undercurrent. Recommended...