Very nice review of The Gabble over here and Greenman Review:
Best story? I really can't say, for much the same reason that I can't pick out the best novel of the entire Polity series. Having read eleven novels and one collection comprising over ten thousand pages of reading, I can only say that all of it is excellent, all of it well-worth reading. If you haven't yet read your way through this series, I envy you; if you have, go get your copy of The Gabble and Other Stories right now before it sells out in hardcover!