An utterly madcap tale, you don't just jump in from page 1, you plunge in and start to drown. It really feels like the middle of a series, rather than the beginning. (There is technically a prequel, but it was published a full ten years after Saffy's Angel, so it doesn't really count in terms of how little set-up there is.)
You absolutely CANNOT take anything in this book seriously. If you start to analyze the ineptitude of the parents, the dysfunction of the family, or really anything other aspect, you will go stark raving bonkers. I mean it.
From stowing away to Italy to eating paint to sitting on your window ledge with your legs dangling outside, let's just say I wouldn't want my kids getting any ideas from the Casson kids. ;)
But because the whole thing is so incredibly over-the-top insane, I don't actually see that being a problem. Kids aren't that stupid.
Overall, it was fun, but I don't feel a deep need to read the others. I desperately wanted more depth, but I suppose you don't need it for the intended audience. I kind of wish things hadn't been hinted at if they weren't going to be fleshed out, but maybe I was reading too much into some things.
One note: the vocabulary is quite British, so some young readers may need explanations of certain terms.