Better answer: these books are really good at kicking the protagonists' heinies. The characters are human -- magically gifted, but human. (Ignore book 2 in the first series, that's temporary.) Their opponents are immortal Djinn who can rearrange reality on a whim. Also: hurricanes, earthquakes, tornadoes, city-sized wildfires... these things are convincingly bigger than you. When the characters have Djinn allies, they find themselves up against super-Djinn, or avatars of the entire Earth's life force, or what have you. At any given moment, our heroes are on the point of being vaporized like ants in a blast furnace. They do not solve their problems by turning into bigger blast furnaces. Generally they are saved by more powerful allies -- who have their own agendas, or bring their own additional troubles to the sandbox. And thus the books are about politics, negotiation, loyalty, and betrayal. (With an obvious undercurrent of adrenaline.) This is way better than a series based on fireworks and supernatural slugfests.
That said, here's why I'm not reading any more by this author: she goes on too long. This is the conclusion of a four-book series that could perfectly well have been two books, which occurs in parallel with a nine-book series that... well, I would have enjoyed it just as much if half the plot threads and two-thirds of the pages had been excised. I realize that I bought all thirteen books and therefore the author wins, but I'm done with that game, honestly.