I think he's great at description and most of his character building, but I really dislike how he uses his world. Or, really, how he doesn't use his world. He keeps hinting at the Others and other fantasy elements, but hardly ever actually does something with it. It seems like the world is there just to create fear or to show the characters travelling.
I don't know, I like certain elements and a few characters, but my interest in the series has dwindled a TON for multiple reasons.