I am a few chapters into Hat Full of Sky and have to say they much darker than you'd expect, not in the imagery but in the tone. You can really feel her struggle all the way through, also rather suprised at the graphic description of Feegle relationships!
I love the little references to wider Discworld peppered throughout that kids reading for the first time wouldn't wink at but we would.
Especially the university bit early in HFS
