>>24805032
The prestige.

In the movie they're cool rockstar magicians obsessed by their competitive rivalry.

In the book they're nerdy guys who exploit being at the right time in history and fooling people with tricks, making them believe they're speaking with their dead relatives and such, and sabotage each other by shouting out how a magic trick is done. Very corny. The movie is about their rivalry and magic itself until the end. The book is also about the felt unseen bond between twins and other relatives.
In the movie one magician is ready for the other in sabotaging the transported man trick. In the book, he turns off the power mid transport and it has unintended horroresque consequences.

There is no real cloning device in the book. Not in the movie either, in my opinion.