The description here on Goodreads is strange. Jirel is not "a little stupid". Just how much she's "a good Catholic girl" is debatable. Also, to say that Moore's work was a reaction to Howard's is simplistic: they were colleagues and friends; Jirel is clearly an inspiration for Dark Agnes de Chastillon, the tales of whom were much admired, in turn, by Moore.
In any case, it's true that Moore has been unfairly overlooked. She was as good as Howard, Lovecraft, or Smith. The first tale in this book, "Black God's Kiss" might beat them all for sheer weirdness.