It's hard to review this book separately from In the Night Garden, because ultimately they're one book in two volumes. And so star ratings are somewhat arbitrary.
Like In the Night Garden, In the Cities of Coin and Spice is a lovely book made up of nested, interconnected stories. The stories are bizarre and fascinating and peopled by interesting, unusual characters. Like the first book, this one contains two "big" stories within the main frame story, and with dozens of nested stories within each of those. I admit to finding the first of the "big" stories here a little disturbing, as it was darker than anything we saw in In the Night Garden, but it is nevertheless very well-told. I also didn't see the pieces coming together at the end of each "big" story in the same exciting way they did in the first book--but here, we see how all the stories come together to form part of the story of the orphan girl, which works very well. Like the first book, In the Cities of Coin and Spice is exceptionally well-written and has lots of strong, complex female characters who have meaningful relationships with each other. Also like the first book, this one has deckle edge pages, which annoyed the hell out of me all over again as I tried to flip back to previous sections as things began to fit together. But that's a minor annoyance in what was a lovely book, one which adds depth to the characters and world we'd previously met, as well as bringing in lots of great new characters and tying everything together well at the end.
Ultimately, I'd recommend The Orphan's Tales to almost anyone, with the caveat that it requires some concentration; I read In the Night Garden and In the Cities of Coin and Spice over about three and a half weeks, during which I was quite busy, and with one other book in between, and despite my being a detail-oriented reader there were occasional references I didn't remember. Ideally you'd read both books over a long weekend with few distractions. One of these days I'll have to read them again--and yes, they are that good.