I enjoyed it. Like any book in the genre they definitely have some eye rolling all the way to the downright cringey moments but overall are pretty good. The cliffhanger that the most recent one ends on pissed me off because it is such a blatant attempt to make you read the next one
As far as falling off a cliff, I wouldn’t say it does that, however, there are 2 of the books, I don’t remember which ones, where not much happens and are kind of place fillers. They still weren’t bad but not at the same pace as the first few. This is coming from someone that his pretty critical on series. I’m of the opinion that every single tv series falls off a cliff after season 3, sons of anarchy, breaking bad, Vikings, etc, all of them