Three stars wholly for Walter Jon Williams's "The Boolean Gate," a delightfully creepy alternate/secret history about Mark Twain and Nicola Tesla that by itself I would have given four. It's a little over-long, but the Mark Twain voice and historical color were spot-on and charming, so it didn't overstay its welcome.
The other stories are predictable pieces of standard monster-based horror. I would give "Hard Silver" two stars for its weird West atmosphere, but the inclusion of Evil Child-Murdering Gypsies drags it down to one. (Seriously, we need this stereotype in 2013? Next you will be having Jews drinking the blood of Christian babies.) And "Raptors" is forgettable through and through.
But read "The Boolean Gate." Just stop afterward.