I think I'm swearing off Gladstone, but I don't have enough information on El-Mohtar yet.

the thing about Pratchett is that at his best, he turns towards the sincere at a critical moment. You always could tell he meant it more because, well, it's not his usual mode. But he didn't always remember to do that, and yeah, the books that are flip all the way through just don't stick with me. The Hatful of Sky books are better about that than most of Discworld.