I don't know what the limit is of the number of books that may be nominated for "Best Novel Hugo" in a given year. This year there were nineteen. Let's have a look, in the order that I read them.
The "Wheel of Time" series concerns three youngsters who are caught up in events far beyond their ability to handle, and in adventures spanning a continent and several years manage to save the world from certain destruction. The story is rightly termed epic fantasy, and the characters are all engaging and well realized. The plot itself, a struggle against a nemesis from mankind's dimly remembered past, doesn't really become clear until book two opens, but that's OK, since book one was kind of an appetizer to get people started reading. Jordan writes well, and Sanderson has no flies on him, either.
Charles Stross' Neptune's Brood is a space opera combined with a mystery, diving from the edge of a solar system into the crushing depths of an ocean world. On the way we learn a little about economics, about meta humanity, and about a relationship a mother might have with her daughters that might have moved Nancy Friday to write something considerably more caustic than My Mother Myself. The story kept me engaged from cover to cover, and the ending was satisfying and amazing.
In the very near future of Mira Grant's (Seanan McGuire) Parasite scientists genetically engineer a symbiotic tapeworm that can do everything from dispensing life saving drugs to suppressing dangerous allergies. Sally, a tapeworm host who's been in an accident, discovers that there's a lot more to these tapeworms than anyone realizes when people start turning into zombies.
Ancillary Justice by Ann Leckie is a leisurely paced journey of discovery. While I was discovering the world of One Esk, One Esk was discovering about moral responsibility and being human. The book engaged me on several levels and didn't disappoint me with its ending, either.
If you want magical battles with humongous guns then Larry Correia's Warbound is your ticket. Jake Sullivan teams up with the Knights of the Grimnoir to save the world from an invading extradimensional monster. Get your battles here!
So which one would I pick to win?
Robert Jordan's "Wheel of Time" series started with a transparent rip-off of Tolkien's Lord of the Rings, The Eye of the World, down to one-to-one mappings of plot and characters. The series picks up after that, but never actually shakes the sense that this is a kid writing a Tolkien fanfic - writing well, mind. Sanderson, working from Jordan's notes, can't really rescue the story from its fate. It's all well written, but I can't get past the fact that this story has already been told.
Larry Correia's "Grimnoir Chronicles" are a lot of fun to read, but I was frankly surprised to find it in the Hugo short list. Larry writes well, don't get me wrong, and if I were to measure this book up against some other action adventure series it would do well. But Larry's story avoids making hard choices. The ending employs the most blatant of deus ex machina, and then reverts everything to a kind of base state, as if none of what happened before mattered. It's what's done on TV all the time, but I personally expect more from serious SF&F.
I'm not really tired of zombies if Grant is going to serve them up with a fresh spin each time. Parasite really has me looking forward to the next one, and I have really no complaints about it. Grant brings her characters to life and doesn't stint on the rest of the story. It's obvious from almost the very beginning where the story is headed, but that's ok because I was looking forward to the journey. The book deserves to win, even if I don't want to pick it as my top pick.
Lecki's Ancillary Justice does start slowly, and the pacing is a bit uneven throughout, but the character One Esk is perhaps the best of her kind I've ever read about. For that reason I was really hard put to choose between her break-out novel and the one I'm picking this year.
Neptune's Brood was kick butt from the very start, as I've come to expect from Stross. His cast of characters is sparse and carefully chosen, and the ones that matter come to life as they make their way. Stross doesn't stint on describing a future that is plausible and amazing. Yes, he might be giving a small political fillip to some people, but I think it's subtle and fully part of the story. He does have to devote more pages to explication than someone writing about more familiar SF tropes would do, but I'm not holding that against him by any means.
If Lecki or Grant win the Hugo I'll be plenty happy. Both have written deserving books, but my pick this year is Stross's Neptune's Brood.