Fan Writers come in two flavors, it seems to me: Reviewers and Analytics. The Reviewers are just that: they take a book/story/movie/video game and break it down into Good/Bad, Read/Don't Read, Watch/Don't Watch categories. The more entertaining Reviewers, of course, have their own well-thought-out definitions of what falls into their personal go/no go, and can explain their conclusions about a specific work in sometimes excruciating detail. (I've been guilty of that myself.) If you stumble upon a good Reviewer, many times the bad reviews are more entertaining than the good ones.
(The late, sorely missed Roger Ebert, of course, was the master at this, as shown here. For my money, he produced the most eviscerating review of a movie I've ever read, commenting on Deuce Bigalow: European Gigolo.)
The Analytics are a bit more wide-ranging: they take an SFF-related subject and drill down into it, commenting on theme, text and subtext, and history. These are generally longer, chewier reads than the Reviewers. Neither approach is better than the other, of course; it depends on what the reader wants at a given moment. But I tend to lean towards the Analytic side of the spectrum (depending on the subject and how well the Analytic tackles it) and my ratings in this category reflect this.
So, this is divided into two parts.
The Resourceful Reviewers
James Davis Nicoll
James is the purest, most voracious book reviewer on this ballot. In 2019, according to his Hugo packet, he read and reviewed 244 books. This works out to about a day and a half of reading and writing per book. Of course, he gets paid for it, so he certainly has an incentive to be fast. But because of this, his reviews are sometimes...a bit shallow. Not that swift and shallow doesn't have its place, mind you, to help you determine quickly if a book might be for you. I just prefer something with a little more meat on its bones.
Alasdair expands the canvas a bit, as he has a newsletter and also does podcasts. In his packet, he offers examples of all of these, which turns out to be quite a bit of (to me) unfocused scattershot material. Again, this is fine if it's your thing. It's not really mine.
I subscribed to Adam's blog, "The Wertzone," on the strength of his Hugo nomination this year. In looking at his Hugo packet entries, I see he has a great interest in what might be considered minutiae, such as the size of the planet Arrakis, and he definitely has a thing for maps. Unfortunately, I....don't.
Paul's Hugo packet was a bit difficult to read, as the Epub formatting was...rather weird, shall we say. (Edit: I went back and tried the PDF version and that was a lot better.) His work is a mix of reviews and interviews, written in an unpretentious, engaging style, with nice details and delving into the books he reviews.
The Accomplished Analytics
Bogi mainly does reviews, but has a laser-sharp, distinct focus: e reviews marginalized authors, and a lot of eir work deals with trans/intersex issues. One of the highlights of eir packet was eir deep dive into Octavia Butler's Xenogenesis trilogy (which I really must get around to one of these days).
(Disclaimer: When Cora was putting her Hugo packet together, she asked on her blog for suggestions as to what to include, and I made a couple of suggestions. So if you don't like something in her packet, I suppose I'm at least partially to blame...)
Cora is a full-on Analytic, and it shows in pretty much everything she writes. She turns out the kind of deep, detailed, long-form pieces you don't see much on the internet anymore. Her Hugo packet shows this off well, with subjects including space opera, hopepunk, steampunk, Star Wars, Star Trek: Discovery, the Dragon Awards, Margaret St. Clair, and--my personal favorite--"Ian McEwan is Clueless About Science Fiction," a delightfully snarky takedown of authors writing in the SFF field without any knowledge of its tropes and traditions.
On this ballot, amidst this competition, Cora Buhlert comes out on top, for me.
Next up: Best Series