The fantasy books series is unfinished, probably the most dissatisfying part of the series. GRRM and his publisher have fallen in the typical morass of milking a series for all its worth, and likely a bit of writer's block, resulting in a watered down spaghetti of a story. Like other series, this series really needs someone to keep them tight and to finish strong. With the TV series, I'm skeptical GRRM can finish within a decade.
That said, the first 3 books have been the most entertaining fantasy books I've read. GRRM was very disciplined to tone down magical elements and stick with character developments. The character developments is where the novels shine.