Generic-but-good girl series, where the girls do lots of adventurous things and are way cooler than the boys, and very matter-of-fact. I liked it a bit as a kid, though I mostly read it for lack of other things to read. I can still name some of the characters and their general vibe (ok, mostly Sprotte), which is a mark in favour of the book.
This is the girl series of Cornelia Funke, she also has a boy series. For teenagers, her Inkworld seris is much better. For the intended age group, I always thought her Thief Lord was in a completely different league.