Book of Sword is awesome, even more so for Sword & Sorcery or Heroic fantasy fans. In fact are any of the anthology books that Dozois and Martin have done together not awesome? I loved all the stories except one, but don't let that one rotten apple spoil the whole barrel because these apples are fit for the gods. I'm sincerely hard pressed to name a favorite of the bunch. Book of Swords is a well-deserved a shout-out the masters; Howard, Lieber, and Moorcock and David Gemmell –he needs to be recognized too- whose works are often overshadowed by the big Epics.
Now it's time someone addresses the elephant in the room; George R. R. Martin. Now I am not a GRRM hater. I was an extremely passionate fan of Song of Fire and Ice –the real name of the GoT series- before anyone was talking about of it. But it needs said Sons of the Dragon is not only straight-up BOORRRING, it has no business in this anthology by even a long stretch. It's not a S&S tale. Heck, I'd argue it's not even a complete short-story at all. It's reads like a really long prolog or a high school book history lesson. Regardless of how bad it is, it doesn't follow an adventure of one or two individuals like all the other stories in this book; it details a history of Targaryen rule in Westeros.
All due respect to Mr. Martin, but either no one has cajones to offer him some creative criticism or they just figured anything he does will automatically get praise and sell books.