4) "Amaryllis", by Carrie Vaughn. Nice enough writing style, but the plot is simply that the bloke in charge of weighing the fishing catch is cheating, against the background of a society where fertility has been restricted; I didn't spot any connection between plot and setting (perhaps there is one and I'm not alert enough to notice it right now) and didn't think the setting, which is the more interesting bit, was sufficiently developed. Not a bad story per se but three out of four BSFA nominees (and three our of four Hugo nominees) are much better.
3) "Ponies", by Kij Johnson. A brilliant, but horrible, very short story about little girls mutilating their familiar spirits as a rite of passage. On a literary level it may well be the best of the nominees (edited to add: and won the Nebula), but I somehow wasn't in the frame of mind to appreciate tales of bits being cut off defenceless creatures.
2) "The Things", by Peter Watts. I put this top of my BSFA ballot, but forgot about it when it came to Hugo nominations. It's a re-telling of John Carpenter's film The Thing from the point of view of the Thing itself, and convincingly conveys the alien entity's disgust with humanity, and its own efforts to work out what is actually going on make an effective counterpoint to the efforts of the humans to defeat it.
1) "For Want of a Nail", by Mary Robinette Kowal. A memorable story about a rogue AI which goes rogue for the best of motives, protecting its closest human friend from the ruthless euthanasia laws of his society, told from the point of view of the young relative who exposes them. I normally hate cute robots - and the fact that this one is called Cordelia did not help - but I found this a strong contrast with, say, "Amaryllis" in that plot and setting are intertwined and explored in the best sfnal tradition.
I'll be happy enough as long as "Amaryllis" doesn't win, but my vote goes to Kowal.
(Previous Hugo category write-up: Best Dramatic Presentation, Short Form.)