The protagonist is a good hearted and well intended character who was handed a position she didn't really want, but hung on to it with surprising determination. The books are entertaing on the surface but there are some things which could be fixed:
My biggest gripe is that the character is always in reactive mode and never stops to think. Worse, she never learned from her mistakes and persisted in repeating them. I never saw her learn or improve.
Then there is the magic which did not seem to follow any consistent pattern. If magic is part of the universe then it should follow consistent rules. Otherwise the story plays out like a game of "Calvin ball" (from the Calvin and Hobbes cartoons) where the rules are made up and change while the game is in progress.
I also consider it bad manners to put the beginning of the next chapter in the end of the previous chapter. Putting the start of the next book in the end of it's predecessor is a cheap trick. There is also an unwritten expectation that a "boxed set" will contain the entire series, but that is not the case here.
Halloween LaVeau is descended from a long line of witches, but she never thought that inheriting LaVeau Manor would be such a curse. After she was voted Worst Witch of the Year, Halloween finally finds her witchy groove - only to lose the Book of Mystics in the process and with that, control of the Underworld.