It's very good but it's written like a historical text, so some will find it dry. It details the Dance Of The Dragons, a civil war between the Targaryens that occurred about 200 years before the start of Game Of Thrones. It also explains the beginning of the end for Targaryen rule: the civil war led to the death of the majority of their dragons.
It has dragon on dragon fights, including nikkas jumping onto other people's dragons mid flight.
And while it does depict how man can kill dragons (their only weakness is their eyes, but they can be killed by a large scorpion trebuchet), it makes clear that a full grown dragon is nearly unstoppable and capable of killing thousands of soldiers in seconds. The only good bet on killing a dragon is with your own dragon...