This isn’t anything in-depth about Gideon the Ninth or Harrow the Ninth. It’s much faster than that.
If “lesbian swords and necromancy in space” doesn’t sound appealing, I guess you should look elsewhere. I thought it was great. Gideon the Ninth has plenty of drama, channels anime in places and ways that I found very satisfying, and delivers convoluted mystery alongside swordplay, violence, and necro-magic. Tamsyn Muir (Tor page, Tumblr, homepage) has my attention.
I’m also enjoying the separate in-universe story The Mysterious Study of Doctor Sex, which takes place before the opening of Gideon the Ninth.
For those who don’t like starting a series until it’s finished… first, that’s silly, it’s not how publishing works. If you want a series to exist, you should damn well read the first book and recommend it to others. Secondly, I don’t think you need to worry as much about that here: while Gideon the Ninth is obviously the first of multiple books, the ending ties the story up neatly and resolves things while still leaving room for a satisfying next story.
I read Gideon the Ninth last year and loved it. I took a little while to really sink into it, but once I had been caught I was stuck in it and couldn’t put the book down. It juked and weaved all over the narrative space; I never felt like it was letting me down by breaking narrative rules, but always felt like I should have seen the next twist coming and was instead surprised by it. I realize that might not be everyone’s cup of tea, but I found it delightful.
I also loved the deeply anchored first person perspective that carried the narration throughout. I took a while to tease out where Gideon’s perspective was reliable and where it wasn’t, but honestly that only made the whole book more fun for me. The generally grisly nature of the story, the YA drama undertones (or just tones sometimes), and the excellent adventure / mystery plot were only made better by Gideon’s grumbling, scathing commentary.
I haven’t started Harrow the Ninth yet.
I’m really looking forward to it.