This latest edition of Gardner Dozois' long-running Year's Best SF anthology series is worth every penny. I enjoyed nearly every story in the volume and found it to be, on the whole, much stronger than previous year's editions.
Highlights of the volume include 'The Birthday of the World' by Ursula Le Guin; in which a race of 'gods' struggle for power, 'Crux' by Albert Cowdrey; a time travel adventure that has more similarities to the old pulp stories than most recent SF, 'Radiant Green Star' by Lucius Shepard; a fabulous story about an orphan's search for his father while he performs in a circus in Vietnam, 'Great Wall of Mars' by Alastair Reynolds; the story of a renegade colony on Mars and attempts to eradicate it, 'On the Orion Line' by Stephen Baxter; a story of war in space that I found to be one of Baxter's most literate and readable stories, 'A Colder War' by Charles Stross; a brilliant meld of Cthulu fiction and Cold War politics, and my favorite story in the volume 'Tendeleo's Story' by Ian McDonald; the story of a young girl in Africa who grows up amid invasion by alien spores.
Like all anthologies, not all stories will please all readers. I found 'Milo and Sylvie' by Eliot Fintushel to be WAY overlong, boring, and without a coherent plot. 'Snowball in Hell' by Brian Stableford bogged down with too much gengineering talk...too many big words, not enough plot extrapolation.
This truly is a collection of the Best SF of the year. There are only a handful of stories that didn't make the book that may have been deserving (stories by Jeffrey Ford, Kage Baker, Charles Sheffield, & Robert Reed spring immediately to mind). By and large the stories in this book are extremely well-written with fascinating plots. Consider 'Oracle' by Greg Egan, a story with thinly veiled characterizations of C.S. Lewis and Alan Turing...this is a story that science fiction is all about. With the exception of the two stories I mentioned earlier, there isn't a sub-par story in this collection. Highly recommended.