The story is that Evie, a self-proclaimed "bad girl" in a bad girl group of friends, is assaulted, but before the guy can get too far she's saved by "good girl" Diane. Diane accidentally kills him, the guy turns out to be the son of a pretty important man, and Evie and Diane become friends.
I never read "The Outsiders" and to be honest, the only thing I know about it is the drama that the author got into years ago on twitter; apparently Hinton takes issue with people interpreting her characters as gay and argued on twitter about it.
So as someone who has no nostalgia or feelings whatsoever for that book, and also as someone who never got around to reading "Moxie," I liked "Bad Girls Never Say Die." But I didn't love it. I liked the characters, especially the dynamic between Evie and Diane, as well as the story and its overarching themes. The pace is a bit slower than I like, and I was never really wowed by anything that happened. The writing is average. My favorite aspect is probably the setting and the super immersive way in which Houston is described.