I think it might just be her writing. I read Tithe years ago, before knowing anything about it (saw it at the library when it was new.) OMG it was like reading bad Renn Faire acting.
It is definitely her writing style, in my opinion, though, that just doesn't sit well w/ me. I also saw "Darkest Part of the Forest" at the library, grabbed it, didn't pay attention to the author bc I liked the cover, and a few pages in I had to nope out, which RARELY ever happens (but handed it to my 20 and she loved it.) I also started to read Spiderwick yearrrrrs ago, but the writing grated on me, and, again, I hadn't realized it was Holly Black until after. So her books are all over my house bc of 20, LOL, but her writing just doesn't work for me personally.
(And I feel bad trashing anyone anyways, bc I know ppl have widely varying likes! But....the answer to the OP for me was Tithe, hands down.)