First off I have to say that the book start with a clever concept around which all the most interesting elements of the book itself are built. Having the English Empire moved in India and permeated by its culture allows the writer to expose some aspect of the English resiliency and to bring at the center of stage culture, people and beliefs that are not standardly encountered in occidental narrative books. This give the reader a sense of wonder that it's not so easy to obtain nowaday. Moreover Mr. Stirling has done his homework and, from what I can appreciate, all the elements are described with luscios details ( even too many details when it comes to dressing or eating !). The frail point of the book is the story, I have to say, which is nothing special indeed, any reader with some fantasy books under his belt will see where it is aiming after some chapters. Seems like all the effort put in the setting has robbed the author of the time to conceive a little more original plot.
Still the book is a good companion for some hours of escapism and even to extend one's knowledge of people and exotic lands, bet you don't know much about Gurkhas'war tactics :-)
In any case if you want to take the most of this book, read it with good historical map or Wikipedia ready or you'll be lost among exotic tribes and religion
Oh also an Hindi disctionary would be good since Mr. Stirling has the annoying habit of putting a foreign word every three in any speech.