The shortlisted stories are listed below in the order I read them with a few comments on each. The title links go to my reviews.
Every Heart a Doorway, by Seanan McGuire (Tor.com publishing)
I loved this novella when I read it last year — it was one of my favourite reads of the year overall — and I nominated it for the Hugo shortlist. Having read the other novellas it remains my favourite, hands down.
A Taste of Honey, by Kai Ashante Wilson (Tor.com publishing)
This novella was interesting and enjoyable and kind of depressing and not exactly an easy read. The ending really made it for me but I also enjoyed the bits getting there... my feelings about it (emotionally, rather than critically) are mixed and I can't say more without spoilers. Critically, this is a strong story that certainly deserves to be shortlisted.
The Dream-Quest of Vellitt Boe, by Kij Johnson (Tor.com publishing)
This story was kind of boring. I belatedly learned that this is probably because it was written in response to a Lovecraft novella which I myself have zero interest in ever reading. The story wasn't badly written on a sentence level, but the pacing was too slow. The ending was interesting, but the slog of getting there puts this story low on the ballot for me.
Penric and the Shaman, by Lois McMaster Bujold (Spectrum Literary Agency)
I have enjoyed Bujold's SF before, but this was the first time I read any of her fantasy. I actually bothered to buy and read the prequel novella before this one, and I enjoyed both. In fact, I enjoyed this second instalment more than the first and plan to read the others at some point. (That point probably being after I've finished the Vorkosigan re-read I'm in the midst of.)
And that brings me to the end of the novellas I actually read. I will say a few words about why I skipped the other two though.
This Census-Taker, by China Miéville (Del Rey / Picador)
This got skipped for two reasons: one, I haven't enjoyed Miéville very much in the past, so I was open to any excuses to skip it (and might have done so anyway), and two, this was a puppy slate nomination, giving me a valid excuse to skip it. Miéville is popular enough to have possibly made the ballot despite the puppies, but I don't really care. His fans can vote for him if they want to, but I was never going to vote him very highly. (Also, the opening couple of sentences were so off-putting).
The Ballad of Black Tom, by Victor LaValle (Tor.com publishing)
I had fully intended to read this one until I found out it was also Lovecraftian. I am glad I saw that review before I started reading. I just. Don't care.
So my ranking for this category wasn't too difficult: Every Heart, Penric, A Taste of Honey, then No Award, then Dream-Quest, leaving off the two I didn't read.