Words are inadequate

I do recommend Gideon. It's a melange of: various kinds of well-thought-out space necromancy; mouthy teenage lesbian feelings and hormones; and internet-culture-circa-2015. But the bones (heh) of the story are a classic country-house murder mystery.

Gideon's the best of them. Harrow spends its front half being Too Clever For Its Own Good (this improves on reread where you can admire how clever it is). And Nona, well, to me Nona reads like "if i want to write two hundred pages about middle-school war-zone-gang politics from the POV of a literal child before getting to any actual plot then by god i will do that and if you complain you'll get another hundred pages of that after the first ten of plot". Plus the whole Space Jesus thing gets annoyingly literalized in Nona.

Honestly I'm put in mind of Jo Walton's dictum about Dune: paraphrased, the first one was good, and each subsequent was half as good as the previous, and she stopped when they became homeopathically good. But Gideon is, wholly and without reservation, Really Good.

(Gideon is also better on reread, true. I'm fine with books being better on reread! I just insist on a baseline level of 'good' on first read. Gideon met that bar trivially, Harrow was occasionally skirting the edges, and Nona likewise but from the wrong side.)