This is one of the most unique worlds I've read in YA. Pretty much all of society is focused around beauty. Which is unfortunate considering every person is born with red eyes, straw-like hair, and grey skin. Fortunately, for a price, the Belles can make you beautiful. It's a world where people change looks frequently and fashion/beauty are the most important things in society. Every scene is described in vivid detail. It's like the magic of Disney World packed into a book.
However. There's a lot of mysteries in this book. Things are not what they seem and all that. But it's very difficult to determine which mysteries are plot-relevant mysteries and which are products of an incomplete world. Why are all the pets the size of teacups? How are they created? Do normal-sized animals exist? Does the government have any responsibilities outside of drafting beauty laws? Do they collect taxes, build schools, pass non-beauty related laws? Are teahouses only in cities? Do people in rural areas come to the city for beauty treatments? How do they afford it? Are most then people their natural color? Even in the cities, it seems wealthy people have trouble affording regular beauty treatments. So what about carpenters and bakers and teachers? We never encounter any grey people in the city but surely not everyone can afford monthly treatments. How do post balloons work? They just magically know where to go? If they magically know where to go, why is the air post necessary?
It was pretty frustrating to be wondering about how some things worked throughout the book and then get to the end to find that it would never be answered. It wasn't part of the mystery, it was just magic I guess.