I just finished reading The Quantum Thief and it has blown me away. It's such a beautiful crazy book from so many different perspectives. His writing is challenging but poetic. It's like watching a pointillism art being painted. But then he takes science fiction to a whole new level. This story is a futuristic path beyond the singularity, where humans are post-physical. So he's painting with colors that haven't been invented yet. You're not going to read this and think, "Oh this is like Firefly with X and Y instead of A and B." It's something new.
It's a challenging read, but worth the trip.